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Sample records for limb scanning based

  1. Atmospheric Waves in MGS TES Limb-Scan Temperatures

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.; Conrath, B. J.; Kaelberer, M. S.; Smith, M. D.

    2014-12-01

    We have quantified the expression of the lowest zonal wavenumber forced and traveling waves evident in the MGS TES Limb-scan temperature retrievals. The results were found to be broadly consistent with the vertically limited and vertically smoothed (although better spatially and temporally resolved) results from the more numerous MGS TES nadir temperature retrievals (e.g., Wilson et al., 2002, Banfield et al., 2003, Banfield et al. 2004). The MGS TES Limb-scan retrievals were used to compute a measure of the Diurnal Kelvin Waves (DK1 And DK2). The structures revealed are consistent with theory, and indicative of the importance of these wave modes at aerobraking altitudes (e.g., Wilson 2000, Forbes & Hagan, 2000, Wilson, 2002). The stationary wave structures revealed in the limb retrievals show the winter polar waves in both hemispheres continue to have their maximum amplitude aligned along the polar vortices, even for altitudes above 4 scale heights. The phase structures in and above the stationary waves revealed by the limb retrievals are consistent with the nadir results and the heat fluxes computed in those analyses (Banfield et al., 2003). The winter polar vortex zonal wavenumber 1 traveling waves continue along the edge of the polar vortex, reaching to 6 or more scale heights altitude in the northern winter and extending between 60N and the north pole. The peak amplitudes for these zonal wavenumber 1 traveling waves were found to lie at about 4 scale heights altitude. The limb retrievals revealed more clear evidence of a northern fall equinoctial global traveling wave mode having expression not only in the mid-latitudes in both hemispheres, but also out of phase above the tropics at altitudes above 4 scale heights. Zonal wavenumber 2 & 3 traveling waves could not be reliably retrieved from the limb retrievals.

  2. Compounding of ultrasound B-scans of a transfemoral residual limb using a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Douglas, Tania S.; Lee, Peter; Solomonidis, Stephan E.; Spence, William D.

    1998-06-01

    Ultrasound may be used for imaging the trans-femoral residual limb in order to provide information for the improvement of prosthetic socket design. Compounding of several ultrasound B-scans is required for obtaining transverse images of the residual limb. In this paper, a method is presented by which a genetic algorithm is used to match B-scans taken in a horizontal plane around the residual limb for image compounding in order to reduce the effects of patient motion during scanning.

  3. [Sequence of venous blood flow alterations in patients after recently endured acute thrombosis of lower-limb deep veins based on the findings of ultrasonographic duplex scanning].

    PubMed

    Tarkovskiĭ, A A; Zudin, A M; Aleksandrova, E S

    2009-01-01

    This study was undertaken to investigate the sequence of alterations in the venous blood flow to have occurred within the time frame of one year after sustained acute thrombosis of the lower-limb deep veins, which was carried out using the standard technique of ultrasonographic duplex scanning. A total of thirty-two 24-to-62-year-old patients presenting with newly onset acute phlebothrombosis were followed up. All the patients were sequentially examined at 2 days, 3 weeks, 3 months, 6 months and 12 months after the manifestation of the initial clinical signs of the disease. Amongst the parameters to determine were the patency of the deep veins and the condition of the valvular apparatus of the deep, superficial and communicant veins. According to the obtained findings, it was as early as at the first stage of the phlebohaemodynamic alterations after the endured thrombosis, i. e., during the acute period of the disease, that seven (21.9%) patients were found to have developed valvular insufficiency of the communicant veins of the cms, manifesting itself in the formation of a horizontal veno-venous reflux, and 6 months later, these events were observed to have occurred in all the patients examined (100%). Afterwards, the second stage of the phlebohaemodynamic alterations was, simultaneously with the process of recanalization of the thrombotic masses in the deep veins, specifically characterized by the formation of valvular insufficiency of the latter, manifesting itself in the form of the development of a deep vertical veno-venous reflux, which was revealed at month six after the onset of the disease in 56.3% of the examined subjects, to be then observed after 12 months in 93.8% of the patients involved. Recanalization of thrombotic masses was noted to commence 3 months after the onset of thrombosis in twelve (37.5%) patients, and after 12 months it was seen to ensue in all the patients (100%), eventually ending in complete restoration of the patency of the affected

  4. Reliability, agreement, and validity of digital weighing scale with MatScan in limb load measurement.

    PubMed

    Kumar, Senthil N S; Omar, Baharudin; Htwe, Ohnmar; Joseph, Leonard H; Krishnan, Jagannathan; Jafarzedah Esfehani, Ali; Min, Lee L

    2014-01-01

    Limb loading measurements serve as an objective evaluation of asymmetrical weight bearing in the lower limb. Digital weighing scales (DWSs) could be used in clinical settings for measurement of static limb loading. However, ambiguity exists whether limb loading measurements of DWSs are comparable with a standard tool such as MatScan. A cross-sectional study composed of 33 nondisabled participants was conducted to investigate the reliability, agreement, and validity of DWSs with MatScan in static standing. Amounts of weight distribution and plantar pressure on the individual lower limb were measured using two DWSs (A, B) and MatScan during eyes open (EO) and eyes closed (EC) conditions. The results showed that intra- and interrater reliability (3, 1) were excellent (0.94-0.97) within and between DWS A and B. Bland-Altman plot revealed good agreement between DWS and MatScan in EO and EC conditions. The area under the receiver operating characteristic curve was significant and identified as 0.68 (p = 0.01). The measurements obtained with DWSs are valid and in agreement with MatScan measurements. Hence, DWSs could be used interchangeably with MatScan and could provide clinicians an objective measurement of limb loading suitable for clinical settings.

  5. Geo-fit Approach to the Analysis of Limb-Scanning Satellite Measurements.

    PubMed

    Carlotti, M; Dinelli, B M; Raspollini, P; Ridolfi, M

    2001-04-20

    We propose a new approach to the analysis of limb-scanning measurements of the atmosphere that are continually recorded from an orbiting platform. The retrieval is based on the simultaneous analysis of observations taken along the whole orbit. This approach accounts for the horizontal variability of the atmosphere, hence avoiding the errors caused by the assumption of horizontal homogeneity along the line of sight of the observations. A computer program that implements the proposed approach has been designed; its performance is shown with a simulated retrieval analysis based on a satellite experiment planned to fly during 2001. This program has also been used for determining the size and the character of the errors that are associated with the assumption of horizontal homogeneity. A computational strategy that reduces the large number of computer resources apparently demanded by the proposed inversion algorithm is described.

  6. Attitude determination from a balloon-borne radiometer using two-sided limb scanning

    NASA Astrophysics Data System (ADS)

    Drummond, J. R.; Turner, D.; Ashton, A.

    1986-03-01

    The determination of the horizontal attitude of a balloon-borne, infrared, limb-scanning radiometer is discussed. In particular, the relationship between scan-angle, as measured by the instrument, and the tangent height of the ray path through the atmosphere is considered. The instrument is unusual in that it scans in two opposite directions. This property is used to derive the scan angle from the same radiance profiles, which are used to determine the constituent profiles, subject only to the assumptions that the attitude is steady, the stratosphere is locally horizontally homogeneous, and the instrumental optical alignment is correct. The results of this determination for the first flight of the Toronto Balloon Radiometer are compared to previous methods of determining the instrumental scan angle and are found to agree to the accuracy with which the comparisons are made. Techniques by which the accuracy and resolution of the two-sided attitude determination could be improved are discussed.

  7. Design and Implementation of a Mechanical Control System for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Bowden, William

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) will use technological improvements in low noise mixers to provide precise data on the Earth's atmospheric composition with high spatial resolution. This project focuses on the design and implementation of a real time control system needed for airborne engineering tests of the SMLS. The system must coordinate the actuation of optical components using four motors with encoder readback, while collecting synchronized telemetric data from a GPS receiver and 3-axis gyrometric system. A graphical user interface for testing the control system was also designed using Python. Although the system could have been implemented with a FPGA-based setup, we chose to use a low cost processor development kit manufactured by XMOS. The XMOS architecture allows parallel execution of multiple tasks on separate threads-making it ideal for this application and is easily programmed using XC (a subset of C). The necessary communication interfaces were implemented in software, including Ethernet, with significant cost and time reduction compared to an FPGA-based approach. For these reasons, the XMOS technology is an attractive, cost effective, alternative to FPGA-based technologies for this design and similar rapid prototyping projects.

  8. Limb-darkening models from along-track operation of the ERBE scanning radiometer

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Manalo-Smith, Natividad; Avis, Lee M.

    1994-01-01

    During January and August 1985, the scanning radiometers of the Earth Radiation Budget Experiment(ERBE) aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 satellite were operated in along-track scanning modes. Along-track scanning permits the study of many measurement problems. It provides the data for developing a limb-darkening model for a single site over a short period of time and also permits the indentification of the scene from data taken at smaller nadir angles. The earth-emitted radiation measured by the scanners has been analyzed to produce limb-darkening models for a variety of scene types. Limb-darkening models relate the radiance in any given direction to the radiant flux. The scene types were computed using measurements within 10 deg of zenith. The models have values near zenith of 1.02-1.09. The typical zenith values of the model are 1.06 for both day and night for ERBS, and for NOAA-9, 1.06 for day and 1.05 for night. Mean models are formed for the ERBS and NOAA-9 results and are found to differ less than 1%, the ERBS results being the higher. The models vary about 1% with latitude near zenith and agree with earlier models that were used to analyze ERBE data typically to 2%.

  9. Thermal Stability of a 4 Meter Primary Reflector for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Cofield, Richard; Kasl, Eldon P.

    2010-01-01

    We describe the fabrication and thermal-stability analysis and test of a composite demonstration model of the Scanning Microwave Limb Sounder (SMLS) primary reflector, having full 4m height and 1/3 the width planned for flight. SMLS is a space-borne heterodyne radiometer which will measure pressure, temperature and atmospheric constituents from thermal emission between 180 and 660 GHz. Current MLS instruments in low Earth orbit scan pencil-beam antennas (sized to resolve about one scale height) vertically over the atmospheric limb. SMLS, planned for the Global Atmospheric Composition Mission of the NRC Decadal Survey, adds azimuthal scanning for better horizontal and temporal resolution and coverage than typical orbit spacing provides. SMLS combines the wide scan range of the parabolic torus with unblocked offset Cassegrain optics. The resulting system is diffraction-limited in the vertical plane but highly astigmatic in the horizontal, having a beam aspect ratio [tilde operator]1:20. Symmetry about the nadir axis ensures that beam shape is nearly invariant over +/-65(white bullet) azimuth. The a feeds a low-noise SIS receiver whose FOV is swept over the reflector system by a small scanning mirror. Using finiteelement models of antenna reflectors and structure, we evaluate thermal deformations and the resulting optical performance for 4 orbital environments and isothermal soak. We compare deformations with photogrammetric measurements made during wide-range (ambient+[-97,+75](white bullet) C) thermal soak tests of the primary in a chamber. This range exceeds predicted orbital soak ranges by large factors, implying in-orbit thermal stability of 0.21(mu)m rms/(white bullet)C, which meets SMLS requirements.

  10. Thermal Stability of a 4 Meter Primary Reflector for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Cofield, Richard E.; Kasl, Eldon P.

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) is a space-borne heterodyne radiometer which will measure pressure, temperature and atmospheric constituents from thermal emission in [180,680] GHz. SMLS, planned for the NRC Decadal Survey's Global Atmospheric Composition Mission, uses a novel toric Cassegrain antenna to perform both elevation and azimuth scanning. This provides better horizontal and temporal resolution and coverage than were possible with elevation-only scanning in the two previous MLS satellite instruments. SMLS is diffraction-limited in the vertical plane but highly astigmatic in the horizontal (beam aspect ratio approx. 1:20). Nadir symmetry ensures that beam shape is nearly invariant over plus or minus 65 deg azimuth. A low-noise receiver FOV is swept over the reflector system by a small azimuth-scanning mirror. We describe the fabrication and thermal-stability test of a composite demonstration primary reflector, having full 4m height and 1/3 the width planned for flight. Using finite-element models of reflectors and structure, we evaluate thermal deformations and optical performance for 4 orbital environments and isothermal soak. We compare deformations with photogrammetric measurements made during soak tests in a chamber. The test temperature range exceeds predicted orbital ranges by large factors, implying in-orbit thermal stability of 0.21 micron rms (root mean square)/C, which meets SMLS requirements.

  11. Limb-darkening functions as derived from along-track operation of the ERBE scanning radiometer for January 1985

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Manalo, Natividad; Suttles, John T.; Walker, Ira

    1989-01-01

    During January 1985, the scanning radiometer aboard the Earth Radiation Budget Satellite was operated to scan along-track. These data have been analyzed to produce limb-darkening functions for Earth emitted radiation, which relate the radiance in any given direction to the radiant exitance. Limb-darkening functions are presented in tabular form and shown as figures for 10 day cases and 12 night cases, corresponding to various scene types and latitude zones. The scene types were computed using measurements within 10 deg of zenith. The limb-darkening functions have values of 1.03 to 1.09 at zenith, with 1.06 being typical. It is found that latitude causes a variation on the order of 1 percent, except for zenith angles greater than 70 deg. These limb-darkening models are about 2 percent higher at zenith than the models derived from Nimbus 7 data.

  12. Study of a Vuilleumier cycle cryogenic refrigerator for detector cooling on the limb scanning infrared radiometer

    NASA Technical Reports Server (NTRS)

    Russo, S. C.

    1976-01-01

    A program to detect and monitor the presence of trace constituents in the earth's atmosphere by using the Limb Scanning Infrared Radiometer (LSIR) is reported. The LSIR, which makes radiometric measurements of the earth's limb radiance profile from a space platform, contains a detector assembly that must be cooled to a temperature of 65 + or - 2 K. The feasibility of cooling the NASA-type detector package with Vuilleumier (VM) cryogenic refrigerator was investigated to develop a preliminary conceptual design of a VM refrigerator that is compatible with a flight-type LSIR instrument. The scope of the LSIR program consists of analytical and design work to establish the size, weight, power consumption, interface requirements, and other important characteristics of a cryogenic cooler that would meet the requirements of the LSIR. The cryogenic cooling requirements under the conditions that NASA specified were defined. Following this, a parametric performance analysis was performed to define the interrelationships between refrigeration characteristics and mission requirements. This effort led to the selection of an optimum refrigerator design for the LSIR mission.

  13. A Deployable 4 Meter 180 to 680 GHz Antenna for the Scanning Microwave Limb Sounder

    NASA Technical Reports Server (NTRS)

    Cofield, Richard E.; Cohen, Eri J.; Agnes, Gregory S.; Stek, Paul C.; Livesey, Nathaniel J.; Read, William G.; Thomson, Mark W.; Kasl, Eldon

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) is a space-borne heterodyne radiometer which will measure pressure, temperature and atmospheric constituents from thermal emission between 180 and 680 GHz. SMLS, planned for the Global Atmospheric Composition Mission of the NRC Decadal Survey, uses a novel toric Cassegrain antenna to perform both elevation and azimuth scanning. These provide better horizontal and temporal resolution and coverage than were possible with elevation-only scanning at typical Low-Earth orbit spacing in the two previous MLS satellite instruments. Development of the SMLS antenna was the focus of a 2006 Small Business Innovative Research (SBIR) program whose phase II culminated in the fabrication and thermal stability testing of a composite demonstration model of the SMLS primary reflector. This reflector has the full 4m height and 1/3 the width planned for flight. An Instrument Incubator Program (IIP) titled "A deployable 4 Meter 180 to 680 GHz antenna for the Scanning Microwave Limb Sounder" continues development of the SMLS antenna with the study of 5 topics: 1) detailed mathematical modeling of the antenna patterns from which we simulate geophysical parameter retrievals in order to establish FOV performance requirements; 2) thorough correlation of finite element model predictions with measurements made on the SBIR reflector. We will again measure deformations of this reflector, under more flight-like thermal gradients, using higher precision metrology techniques available in a new large-aperture facility at JPL; 3) fabrication of a full-width primary reflector whose asbuilt surface figure will better meet the figure requirements of SMLS than did the SBIR reflector; 4) integration of the primary with other reflectors, and with residual front ends built in a 2007 IIP, in a breadboard antenna; and finally 5) RF testing of the breadboard on a Near Field Range at JPL. We report on significant progress in 3 areas of the current IIP: development of

  14. Baffle design for earth radiation rejection in the Cryogenic Limb-Scanning Interferometer/Radiometer

    NASA Technical Reports Server (NTRS)

    Bremer, J. C.

    1980-01-01

    The Cryogenic Limb-Scanning Interferometer/Radiometer (CLIR) is being developed to observe infrared emissions of the earth's upper atmosphere from space. The earth's surface is an extended source of intense background radiation with a small angular separation from the desired scene. The CLIR employs an off-axis Gregorian Telescope whose primary mirror and baffles are cooled by an open-cycle cryogen system. A system of specular annular baffles has been developed to minimize both stray light problems and cryogen consumption by retro-mapping the aperture into itself. Each off-axis ray which enters the aperture and strikes the specular baffle surface is reflected so that it passes out of the aperture and is not absorbed on a cryogenic surface. The specular baffle which lies closest to the aperture is an ellipsoid whose foci trace out the circular aperture on revolution about the axis. Its theoretical 'ray trace' efficiency is 100 percent. A subsequent baffle has an elliptical cross section whose near focus traces out the central hole in the ellipsoidal baffle and whose far focus traces out the aperture. Its theoretical efficiency is about 90 percent. These baffles reduce the earth radiation heat load on the cryogenic cooler by an order of magnitude, changing it from the dominant cause of cryogen consumption to a relatively small effect. An aperture shield is also desirable to reduce cryogen consumption, stray light, and contamination.

  15. Constraints on JN2O5 from balloon-borne limb scanning measurements of NO2 in the tropics

    NASA Astrophysics Data System (ADS)

    Kritten, Lena; Butz, Andre; Deutschmann, Tim; Dorf, Marcel; Kreycy, Sebastian; Prados-Roman, Cristina; Pfeilsticker, Klaus

    2010-05-01

    The NOx ozone cycle (NOx = NO + NO2) is of great importance for the budget of stratospheric ozone and in future may even become more important due to increasing stratospheric N2O concentrations (Ravishankara et al., 2009). A regulating process for the amount of stratospheric NOx and thus for the efficiency of the NOx mediated ozone loss cycle is photolytic release of N2O5 at daytime since N2O5 acts as a nighttime reservoir gas for stratospheric NOx radicals. Observations of UV/vis scattered skylight by balloon-borne limb scanning spectrometry support the detection of time dependent trace gas and radical profiles, in particular of NO2. Here we present balloon borne measurements of time dependent NO2 profiles from the tropical stratosphere - taken at north-eastern Brazil (5° S, 43° W) in June 2005 - where excess stratospheric ozone is produced and transported to higher latitudes by the Brewer-Dobson circulation. The photolysis rate of N2O5 - uncertain by a factor of 2 (JPL-2006) - is constrained from the comparison of the measured and modelled diurnal variation of NO2. For the photochemical model initial conditions are based on our own observations of O3 and NO2, MIPAS-B measurements and on output of the 3-D SLIMCAT model. The kinetic and thermodynamic parameters and absorption cross-sections are taken from the JPL-2006 compilation (Sander et. al, 2006). Overall it is found that, the observed rate of diurnal NO2 increase requires a N2O5 photolysis frequency at the upper limit of values possible according to the uncertainty range given by the JPL-2006 compilation. In conclusion it suggested that the NOx mediated ozone loss in the tropical stratosphere is probably larger than assumed by many photochemical models, and in future may even relatively become more important.

  16. Limb-darkening functions as derived from along-track operation of the ERBE scanning radiometers for August 1985

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Manalo, Natividad D.; Avis, Lee M.

    1990-01-01

    During August 1985, the scanning radiometers of the Earth Radiation Budget Experiment aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 satellite were operated in along-track scanning modes. These data were analyzed to produce limb darkening functions for Earth-emitted radiation, which relates the radiance in any given direction to the radiant exitence. Limb darkening functions are presented and shown as figures for day and night for each spacecraft. The scene types were computed using measurements within 10 deg of zenith. The models have values near zenith of 1.02 to 1.09, with values near 1.06 being typical. The typical value of the model is 1.06 for both day and night for ERBS, and for NOAA-9, the typical value at zenith is 1.06 for day and 1.05 for night. Mean models are formed for the ERBS and for the NOAA-9 results and are found to differ less than 1 percent, the ERBS results being the higher. The models vary about 1 percent with latitude near zenith.

  17. New method for simultaneous gas and aerosol retrievals from space limb-scanning spectral observation of the atmosphere.

    PubMed

    Oshchepkov, Sergey; Sasano, Yasuhiro; Yokota, Tatsuya

    2002-07-20

    This study concerns the development of a new inversion method for simultaneous gas and aerosol retrievals in the upper layers of the atmosphere from limb-viewing multiwavelength-transmission infrared measurements. In this method, concentrations of gas species such as O3, NO2, HNO3, N2O, CH4, and H2O, and spectral dependences of the aerosol extinction coefficient are retrieved simultaneously. When this is done, smoothness constraints on the desired spectral dependencies of the aerosol extinction coefficient are used as an a priori assumption. The method is used in the treating of synthetic transmission spectra of the Improved Limb Atmospheric Spectrometer, which is based on the solar occultation technique and was on board the Advanced Earth Observing Satellite. A set of numerical tests shows the efficiency of the method.

  18. Center to limb scans of the Saturnian equator at 20 microns

    NASA Technical Reports Server (NTRS)

    Caldwell, J.; Gillett, F. C.; Nolt, I. G.; Tokunaga, A.

    1978-01-01

    Spatially resolved area scans of the equator of Saturn through filters at 17.8, 19.7, and 22.9 microns are used to evaluate proposed model atmospheres from the literature. The present observations demonstrate that the equatorial thermal structure has not changed measurably in the last three years.

  19. Clustering-based limb identification for pressure ulcer risk assessment.

    PubMed

    Baran Pouyan, M; Nourani, M; Pompeo, M

    2015-01-01

    Bedridden patients have a high risk of developing pressure ulcers. Risk assessment for pressure ulceration is critical for preventive care. For a reliable assessment, we need to identify and track the limbs continuously and accurately. In this paper, we propose a method to identify body limbs using a pressure mat. Three prevalent sleep postures (supine, left and right postures) are considered. Then, predefined number of limbs (body parts) are identified by applying Fuzzy C-Means (FCM) clustering on key attributes. We collected data from 10 adult subjects and achieved average accuracy of 93.2% for 10 limbs in supine and 7 limbs in left/right postures.

  20. Synthetic holography based on scanning microcavity

    NASA Astrophysics Data System (ADS)

    Di Donato, A.; Farina, M.

    2015-11-01

    Synthetic optical holography (SOH) is an imaging technique, introduced in scanning microscopy to record amplitude and phase of a scattered field from a sample. In this paper, it is described a novel implementation of SOH through a lens-free low-coherence system, based on a scanning optical microcavity. This technique combines the low-coherence properties of the source with the mutual interference of scattered waves and the resonant behavior of a micro-cavity, in order to realize a high sensitive imaging system. Micro-cavity is compact and realized by approaching a cleaved optical fiber to the sample. The scanning system works in an open-loop configuration without the need for a reference wave, usually required in interferometric systems. Measurements were performed over calibration samples and a lateral resolution of about 1 μm is achieved by means of an optical fiber with a Numerical Aperture (NA) equal to 0.1 and a Mode Field Diameter (MDF) of 5.6 μm.

  1. SCAN+

    SciTech Connect

    Kenneth Krebs, John Svoboda

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.

  2. Limbform: a functional ontology-based database of limb regeneration experiments

    PubMed Central

    Lobo, Daniel; Feldman, Erica B.; Shah, Michelle; Malone, Taylor J.; Levin, Michael

    2014-01-01

    Summary: The ability of certain organisms to completely regenerate lost limbs is a fascinating process, far from solved. Despite the extraordinary published efforts during the past centuries of scientists performing amputations, transplantations and molecular experiments, no mechanistic model exists yet that can completely explain patterning during the limb regeneration process. The lack of a centralized repository to enable the efficient mining of this huge dataset is hindering the discovery of comprehensive models of limb regeneration. Here, we introduce Limbform (Limb formalization), a centralized database of published limb regeneration experiments. In contrast to natural language or text-based ontologies, Limbform is based on a functional ontology using mathematical graphs to represent unambiguously limb phenotypes and manipulation procedures. The centralized database currently contains >800 published limb regeneration experiments comprising many model organisms, including salamanders, frogs, insects, crustaceans and arachnids. The database represents an extraordinary resource for mining the existing knowledge of functional data in this field; furthermore, its mathematical nature based on a functional ontology will pave the way for artificial intelligence tools applied to the discovery of the sought-after comprehensive limb regeneration models. Availability and implementaion: The Limbform database is freely available at http://limbform.daniel-lobo.com. Contact: michael.levin@tufts.edu PMID:25170026

  3. [Vein Scanning Projection Instrument Based on Two-Dimensional Scanning Mirror].

    PubMed

    Meng, Ya; Wu, Zhichao; Xu, Changping; Qian, Yinbo

    2015-09-01

    With the development of science and technology, new medical equipments is toward the direction of intelligent and portable. In order to assist medical personnel to patients with blood, developing from previous devices, a new kind of vein locating projection instrument based on two-dimensional scanning mirror is put forward. It can scan and project vein image using a scanning mirror. The related algorithm is also be improved, make vein scan projection more practical. The system finally set up can perform well in vein scan projection.

  4. Feasibility study for joint retrieval of air density and ozone in the stratosphere and mesosphere with the limb-scan technique.

    PubMed

    Guo, Xia; Lu, Daren

    2006-12-10

    Air density is a key sensing object for its high variability especially in the mesosphere, and ozone plays an important role in the physical, chemical, and radiant processes in the atmosphere system. Therefore it is essential to obtain their global vertical distributions jointly with high precision and vertical resolution. There is little work on joint retrieval of air density and ozone distributions using the ultraviolet limb-scan technique, although much work has been done on ozone measurement. Numerical simulations of joint air density and ozone retrieval in the middle atmosphere (20-90 km) are carried out using limb-scattered radiances at four bands (255, 300, 320, and 340 nm). Results show that joint retrieval of dual parameters using the limb-scan technique is feasible with high precision in nearly the whole region concerned, where air density and ozone have a precision of 1%-2% and 3%-5%, respectively, provided that high measurement precision and accurate correction of multiple-scattered radiance at long ultraviolet bands are ensured.

  5. Mechanism of Kinect-based virtual reality training for motor functional recovery of upper limbs after subacute stroke.

    PubMed

    Bao, Xiao; Mao, Yurong; Lin, Qiang; Qiu, Yunhai; Chen, Shaozhen; Li, Le; Cates, Ryan S; Zhou, Shufeng; Huang, Dongfeng

    2013-11-05

    The Kinect-based virtual reality system for the Xbox 360 enables users to control and interact with the game console without the need to touch a game controller, and provides rehabilitation training for stroke patients with lower limb dysfunctions. However, the underlying mechanism remains unclear. In this study, 18 healthy subjects and five patients after subacute stroke were included. The five patients were scanned using functional MRI prior to training, 3 weeks after training and at a 12-week follow-up, and then compared with healthy subjects. The Fugl-Meyer Assessment and Wolf Motor Function Test scores of the hemiplegic upper limbs of stroke patients were significantly increased 3 weeks after training and at the 12-week follow-up. Functional MRI results showed that contralateral primary sensorimotor cortex was activated after Kinect-based virtual reality training in the stroke patients compared with the healthy subjects. Contralateral primary sensorimotor cortex, the bilateral supplementary motor area and the ipsilateral cerebellum were also activated during hand-clenching in all 18 healthy subjects. Our findings indicate that Kinect-based virtual reality training could promote the recovery of upper limb motor function in subacute stroke patients, and brain reorganization by Kinect-based virtual reality training may be linked to the contralateral sensorimotor cortex.

  6. Quantifying limb movements in epileptic seizures through color-based video analysis.

    PubMed

    Lu, Haiping; Pan, Yaozhang; Mandal, Bappaditya; Eng, How-Lung; Guan, Cuntai; Chan, Derrick W S

    2013-02-01

    This paper proposes a color-based video analytic system for quantifying limb movements in epileptic seizure monitoring. The system utilizes colored pyjamas to facilitate limb segmentation and tracking. Thus, it is unobtrusive and requires no sensor/marker attached to patient's body. We employ Gaussian mixture models in background/foreground modeling and detect limbs through a coarse-to-fine paradigm with graph-cut-based segmentation. Next, we estimate limb parameters with domain knowledge guidance and extract displacement and oscillation features from movement trajectories for seizure detection/analysis. We report studies on sequences captured in an epilepsy monitoring unit. Experimental evaluations show that the proposed system has achieved comparable performance to EEG-based systems in detecting motor seizures.

  7. Lens based adaptive optics scanning laser ophthalmoscope.

    PubMed

    Felberer, Franz; Kroisamer, Julia-Sophie; Hitzenberger, Christoph K; Pircher, Michael

    2012-07-30

    We present an alternative approach for an adaptive optics scanning laser ophthalmoscope (AO-SLO). In contrast to other commonly used AO-SLO instruments, the imaging optics consist of lenses. Images of the fovea region of 5 healthy volunteers are recorded. The system is capable to resolve human foveal cones in 3 out of 5 healthy volunteers. Additionally, we investigated the capability of the system to support larger scanning angles (up to 5°) on the retina. Finally, in order to demonstrate the performance of the instrument images of rod photoreceptors are presented.

  8. Motion compensation in a tomographic ultrasound imaging system: Toward volumetric scans of a limb for prosthetic socket design.

    PubMed

    Ranger, Bryan J; Feigin, Micha; Pestrov, Nikita; Zhang, Xiang; Lempitsky, Victor; Herr, Hugh M; Anthony, Brian W

    2015-08-01

    Current methods of prosthetic socket fabrication remain subjective and ineffective at creating an interface to the human body that is both comfortable and functional. Though there has been recent success using methods like magnetic resonance imaging and biomechanical modeling, a low-cost, streamlined, and repeatable process has not been fully demonstrated. Medical ultrasonography, which has significant potential to expand its clinical applications, is being pursued to acquire data that may quantify and improve the design process and fabrication of prosthetic sockets. This paper presents a new multi-modal imaging approach for acquiring volumetric images of a human limb, specifically focusing on how motion of the limb is compensated for using optical imagery.

  9. Scanning rain gauge based on photo electricity

    NASA Astrophysics Data System (ADS)

    Huang, Fei-long; Li, Yuan-hong

    2008-03-01

    A non-contact rain gauge with photo electricity technology is introduced in this paper. Dimensional distribution of rain inside a traditional rain gauge does not need to be changed, and the rainwater falls freely to the ground, so this new rain gauge doesn't need to be cleared as a traditional rain gauge does frequently. And then a capacitor is used as a switch that would drive LED light to scan and drive photo electricity inducing element Charge Coupled Device (CCD) to detect when it is induced by the falling drips. Light through a convex lens would scan the drips and project them on CCD across. Electrical signal is produced when CCD detects the shadow after another convex lens. The drips whose diameter is 0.3 millimeter can be distinguished and so as smaller drips of 0.1 millimeter if high-resolution CCD is used. After an amplifier the electrical signal would be transformed into digital signal and would be used to calculate the volume of rain. The Central Processing Unit on main control board gives commands to scanning trigger and controls interrupts from process of data acquisition and calculation. The non-contact photo electricity measurement can detect raindrops of different size. Parallel light projects every raindrop in space on CCD and tells its diameter exactly. So it gives satisfying precision and other useful data such as spectrum of raindrops. Further more, velocity of raindrop would be acquired according to its size. The system needs low cost with universal CCD and Single Chip Micyoco (SCM), and it is worth advocating.

  10. Correcting scan-to-scan response variability for a radiochromic film-based reference dosimetry system

    SciTech Connect

    Lewis, David; Devic, Slobodan

    2015-10-15

    Purpose: In radiochromic film dosimetry systems, measurements are usually obtained from film images acquired on a CCD-based flatbed scanner. The authors investigated factors affecting scan-to-scan response variability leading to increased dose measurement uncertainty. Methods: The authors used flatbed document scanners to repetitively scan EBT3 radiochromic films exposed to doses 0–1000 cGy, together with three neutral density filters and three blue optical filters. Scanning was performed under two conditions: scanner lid closed and scanner lid opened/closed between scans. The authors also placed a scanner in a cold room at 9 °C and later in a room at 22 °C and scanned EBT3 films to explore temperature effects. Finally, the authors investigated the effect of altering the distance between the film and the scanner’s light source. Results: Using a measurement protocol to isolate the contribution of the CCD and electronic circuitry of the scanners, the authors found that the standard deviation of response measurements for the EBT3 film model was about 0.17% for one scanner and 0.09% for the second. When the lid of the first scanner was opened and closed between scans, the average scan-to-scan difference of responses increased from 0.12% to 0.27%. Increasing the sample temperature during scanning changed the RGB response values by about −0.17, −0.14, and −0.05%/°C, respectively. Reducing the film-to-light source distance increased the RBG response values about 1.1, 1.3, and 1.4%/mm, respectively. The authors observed that films and film samples were often not flat with some areas up to 8 mm away from the scanner’s glass window. Conclusions: In the absence of measures to deal with the response irregularities, each factor the authors investigated could lead to dose uncertainty >2%. Those factors related to the film-to-light source distance could be particularly impactful since the authors observed many instances where the curl of film samples had the

  11. Golden angle based scanning for robust corneal topography with OCT

    PubMed Central

    Wagner, Joerg; Goldblum, David; Cattin, Philippe C.

    2017-01-01

    Corneal topography allows the assessment of the cornea’s refractive power which is crucial for diagnostics and surgical planning. The use of optical coherence tomography (OCT) for corneal topography is still limited. One limitation is the susceptibility to disturbances like blinking of the eye. This can result in partially corrupted scans that cannot be evaluated using common methods. We present a new scanning method for reliable corneal topography from partial scans. Based on the golden angle, the method features a balanced scan point distribution which refines over measurement time and remains balanced when part of the scan is removed. The performance of the method is assessed numerically and by measurements of test surfaces. The results confirm that the method enables numerically well-conditioned and reliable corneal topography from partially corrupted scans and reduces the need for repeated measurements in case of abrupt disturbances. PMID:28270961

  12. Golden angle based scanning for robust corneal topography with OCT.

    PubMed

    Wagner, Joerg; Goldblum, David; Cattin, Philippe C

    2017-02-01

    Corneal topography allows the assessment of the cornea's refractive power which is crucial for diagnostics and surgical planning. The use of optical coherence tomography (OCT) for corneal topography is still limited. One limitation is the susceptibility to disturbances like blinking of the eye. This can result in partially corrupted scans that cannot be evaluated using common methods. We present a new scanning method for reliable corneal topography from partial scans. Based on the golden angle, the method features a balanced scan point distribution which refines over measurement time and remains balanced when part of the scan is removed. The performance of the method is assessed numerically and by measurements of test surfaces. The results confirm that the method enables numerically well-conditioned and reliable corneal topography from partially corrupted scans and reduces the need for repeated measurements in case of abrupt disturbances.

  13. EEG-based BCI for the linear control of an upper-limb neuroprosthesis.

    PubMed

    Vidaurre, Carmen; Klauer, Christian; Schauer, Thomas; Ramos-Murguialday, Ander; Müller, Klaus-Robert

    2016-11-01

    Assistive technologies help patients to reacquire interacting capabilities with the environment and improve their quality of life. In this manuscript we present a feasibility study in which healthy users were able to use a non-invasive Motor Imagery (MI)-based brain computer interface (BCI) to achieve linear control of an upper-limb functional electrical stimulation (FES) controlled neuro-prosthesis. The linear control allowed the real-time computation of a continuous control signal that was used by the FES system to physically set the stimulation parameters to control the upper-limb position. Even if the nature of the task makes the operation very challenging, the participants achieved a mean selection accuracy of 82.5% in a target selection experiment. An analysis of limb kinematics as well as the positioning precision was performed, showing the viability of using a BCI-FES system to control upper-limb reaching movements. The results of this study constitute an accurate use of an online non-invasive BCI to operate a FES-neuroprosthesis setting a step toward the recovery of the control of an impaired limb with the sole use of brain activity.

  14. Assessment of Upper Limb Motor Dysfunction for Children with Cerebral Palsy Based on Muscle Synergy Analysis

    PubMed Central

    Tang, Lu; Chen, Xiang; Cao, Shuai; Wu, De; Zhao, Gang; Zhang, Xu

    2017-01-01

    Muscle synergies are considered to be building blocks underlying motor behaviors. The goal of this study is to explore an objective and effective method to assess the upper limb motor dysfunction of cerebral palsy (CP) children from the aspect of muscle synergy analysis. Fourteen CP children and 10 typically developed (TD) children were recruited to perform three similar upper limb motion tasks related to the movements of elbow and shoulder joints, and surface electromyographic (sEMG) signals were recorded from 10 upper arm and shoulder muscles involved in the defined tasks. Non-negative matrix factorization algorithm was used to extract muscle synergies and the corresponding activation patterns during three similar tasks. For each subject in TD group, four muscle synergies were extracted in each task. Whereas, fewer mature synergies were recruited in CP group, and many abnormal synergy structures specific to CP group appeared. In view of neuromuscular control strategy differences, three synergy-related parameters were proposed and synergy structure similarity coefficient was found to have high ability in depicting the inter-subject similarity within task and the intra-subject similarity between tasks. Seven upper limb assessment (UPA) metrics, which were defined as the combinations of synergy structure similarity coefficients of three tasks, were proposed to assess the upper limb motor function of CP children. The experimental results demonstrated that these UPA metrics were able to assess upper limb motor function comprehensively and effectively. The proposed assessment method can serve as a promising approach to quantify the abnormality of muscle synergies, thus offering potential to derive a physiologically based quantitative index for assessing upper limb motor function in CP clinical diagnosis and rehabilitation. PMID:28386223

  15. LINEAR SCANNING METHOD BASED ON THE SAFT COARRAY

    SciTech Connect

    Martin, C. J.; Martinez-Graullera, O.; Romero, D.; Ullate, L. G.; Higuti, R. T.

    2010-02-22

    This work presents a method to obtain B-scan images based on linear array scanning and 2R-SAFT. Using this technique some advantages are obtained: the ultrasonic system is very simple; it avoids the grating lobes formation, characteristic in conventional SAFT; and subaperture size and focussing lens (to compensate emission-reception) can be adapted dynamically to every image point. The proposed method has been experimentally tested in the inspection of CFRP samples.

  16. Stereo vision based hand-held laser scanning system design

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Xu, Jun; Wang, Jinming

    2011-11-01

    Although 3D scanning system is used more and more broadly in many fields, such computer animate, computer aided design, digital museums, and so on, a convenient scanning device is expansive for most people to afford. In another hand, imaging devices are becoming cheaper, a stereo vision system with two video cameras cost little. In this paper, a hand held laser scanning system is design based on stereo vision principle. The two video cameras are fixed tighter, and are all calibrated in advance. The scanned object attached with some coded markers is in front of the stereo system, and can be changed its position and direction freely upon the need of scanning. When scanning, the operator swept a line laser source, and projected it on the object. At the same time, the stereo vision system captured the projected lines, and reconstructed their 3D shapes. The code markers are used to translate the coordinate system between scanned points under different view. Two methods are used to get more accurate results. One is to use NURBS curves to interpolate the sections of the laser lines to obtain accurate central points, and a thin plate spline is used to approximate the central points, and so, an exact laser central line is got, which guards an accurate correspondence between tow cameras. Another way is to incorporate the constraint of laser swept plane on the reconstructed 3D curves by a PCA (Principle Component Analysis) algorithm, and more accurate results are obtained. Some examples are given to verify the system.

  17. Scan-Based Implementation of JPEG 2000 Extensions

    NASA Technical Reports Server (NTRS)

    Rountree, Janet C.; Webb, Brian N.; Flohr, Thomas J.; Marcellin, Michael W.

    2001-01-01

    JPEG 2000 Part 2 (Extensions) contains a number of technologies that are of potential interest in remote sensing applications. These include arbitrary wavelet transforms, techniques to limit boundary artifacts in tiles, multiple component transforms, and trellis-coded quantization (TCQ). We are investigating the addition of these features to the low-memory (scan-based) implementation of JPEG 2000 Part 1. A scan-based implementation of TCQ has been realized and tested, with a very small performance loss as compared with the full image (frame-based) version. A proposed amendment to JPEG 2000 Part 2 will effect the syntax changes required to make scan-based TCQ compatible with the standard.

  18. Two anatomic resources of canine pelvic limb muscles based on CT and MRI.

    PubMed

    Sunico, Sarena K; Hamel, Corentin; Styner, Martin; Robertson, Ian D; Kornegay, Joe N; Bettini, Chris; Parks, Jerry; Wilber, Kathy; Smallwood, J Edgar; Thrall, Donald E

    2012-01-01

    Advances in magnetic resonance (MR) imaging and three-dimensional (3D) modeling software provide the tools necessary to create sophisticated, interactive anatomic resources that can assist in the interpretation of MR images of extremities, and learning the structure and function of limb musculature. Modeling provides advantages over dissection or consultation of print atlases because of the associated speed, flexibility, 3D nature, and elimination of superimposed arrows and labels. Our goals were to create a diagnostic atlas of pelvic limb muscles that will facilitate interpretation of MR images of patients with muscle injury and to create a 3D model of the canine pelvic limb musculature to facilitate anatomic learning. To create these resources, we used structural segmentation of MR images, a process that groups image pixels into anatomically meaningful regions. The Diagnostic Atlas is an interactive, multiplanar, web-based MR atlas of the canine pelvic limb musculature that was created by manually segmenting clinically analogous MR sequences. Higher resolution volumetric MR and computed tomography (CT) data were segmented into separately labeled volumes of data and then transformed into a multilayered 3D computer model. The 3D Model serves as a resource for students of gross anatomy, encouraging integrative learning with its highly interactive and selective display capabilities. For clinicians, the 3D Model also serves to bridge the gap between topographic and tomographic anatomy, displaying both formats alongside, or even superimposed over each other. Both projects are hosted on an open-access website, http://3dvetanatomy.ncsu.edu/

  19. Update on MEMS-based scanned beam imager

    NASA Astrophysics Data System (ADS)

    James, Richard; Gibson, Greg; Metting, Frank; Davis, Wyatt; Drabe, Christian

    2007-01-01

    In 2004, Microvision presented "Scanned Beam Medical Imager" as an introduction to our MEMS-based, full color scanned beam imaging system. This presentation will provide an update of the technological advancements since this initial work from 2004. This recent work includes the development of functional prototypes that are much smaller than previous prototypes using a design architecture that is easily scalable. Performance has been significantly improved by increasing the optical field of views and video refresh rate. Real-time image processing capabilities have been developed to enhance the image quality and functionality over a wide range of operating conditions. Actual images of various objects will be presented.

  20. Mathematical model for light scanning system based on circular laser

    NASA Astrophysics Data System (ADS)

    Xu, Peiquan; Yao, Shun; Lu, Fenggui; Tang, Xinhua; Zhang, Wei

    2005-11-01

    A novel light scanning system based on circular laser trajectory for welding robot is developed. With the help of image processing technique, intelligent laser welding could be realized. According to laser triangulation algorithm and Scheimpflug condition, mathematical model for circular laser vision is built. This scanning system projects circular laser onto welded seams and recovers the depth of the welded seams, escapes from shortcomings of less information, explains ambiguity and single tracking direction inherent in "spot" or "line" type laser trajectory. Three-dimensional (3D) model for welded seams could be recognized after depth recovery. The imaging error is investigated also.

  1. [Moving Mirror Scanning System Based on the Flexible Hinge Support].

    PubMed

    Xie, Fei; Feng, Fei; Wang, Fu-bei; Wu, Qiong-shui; Zeng, Li-bo

    2015-08-01

    In order to improve moving mirror drive of Fourier transform infrared spectrometer, we design a dynamic scanning system based on flexible hinge support. Using the flexible hinge support way and the voice coil motor drive mode. Specifically, Using right Angle with high accuracy high stability type flexible hinge support mechanism support moving mirror, dynamic mirror can be moved forward and backward driven by voice coil motor reciprocating motion, DSP control system to control the moving mirror at a constant speed. The experimental results show that the designed of moving mirror scanning system has advantages of stability direction, speed stability, superior seismic performance.

  2. [Research on optimization of lower limb parameters of cardiopulmonary resuscitation simulation model based on genetic algorithm].

    PubMed

    Xu, Lin

    2014-10-01

    Sudden cardiac arrest is one of the critical clinical syndromes in emergency situations. A cardiopulmonary resuscitation (CPR) is a necessary curing means for those patients with sudden cardiac arrest. In order to simulate effectively the hemodynamic effects of human under AEI-CPR, which is active compression-decompression CPR coupled with enhanced external counter-pulsation and inspiratory impedance threshold valve, and research physiological parameters of each part of lower limbs in more detail, a CPR simulation model established by Babbs was refined. The part of lower limbs was divided into iliac, thigh and calf, which had 15 physiological parameters. Then, these 15 physiological parameters based on genetic algorithm were optimized, and ideal simulation results were obtained finally.

  3. Training strategies for a lower limb rehabilitation robot based on impedance control.

    PubMed

    Hu, Jin; Hou, Zengguang; Zhang, Feng; Chen, Yixiong; Li, Pengfeng

    2012-01-01

    This paper proposes three training strategies based on impedance control, including passive training, damping-active training and spring-active training, for a 3-DOF lower limb rehabilitation robot designed for patients with paraplegia or hemiplegia. Controllers with similar structure are developed for these training strategies, consisting of dual closed loops, the outer impedance control loop and the inner position/velocity control loop, known as position-based impedance control method. Simulation results verify that position-based impedance control approach is feasible to accomplish the training strategies.

  4. MEMS-BASED 3D CONFOCAL SCANNING MICROENDOSCOPE USING MEMS SCANNERS FOR BOTH LATERAL AND AXIAL SCAN

    PubMed Central

    Liu, Lin; Wang, Erkang; Zhang, Xiaoyang; Liang, Wenxuan; Li, Xingde; Xie, Huikai

    2014-01-01

    A fiber-optic 3D confocal scanning microendoscope employing MEMS scanners for both lateral and axial scan was designed and constructed. The MEMS 3D scan engine achieved a lateral scan range of over ± 26° with a 2D MEMS scanning micromirror and a depth scan of over 400 μm with a 1D MEMS tunable microlens. The lateral resolution and axial resolution of this system were experimentally measured as 1.0 μm and 7.0 μm, respectively. 2D and 3D confocal reflectance images of micro-patterns, micro-particles, onion skins and acute rat brain tissue were obtained by this MEMS-based 3D confocal scanning microendoscope. PMID:25013304

  5. Detection of defects in optics based on scanning

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Bai, Jian; Liang, Yiyong; Wang, Kaiwei; Lu, Qianbo; Zhang, Sai

    2015-08-01

    In this paper, a method to detect internal pocks and bubbles of optical elements based on laser line source scanning is proposed. In dark field environment, a laser line source is used to illuminate from one side of the glass under test, a high-resolution CCD camera is used to take pictures in front of the glass sample. Images which contain information of defects are acquired through rough scanning and accurate scanning. Accurate three-dimensional coordinates of the internal defects are acquired after image processing, which descript the characteristic information of internal defects quantificationally. Compared with the microscope imaging measurement, this proposed detection of defects in optics based on laser line source scanning has a relative aberration smaller than 2%. In addition, the detection time is approximately reduced to 20 minutes from 1 hour dramatically. The analysis indicates that the error of the position of defects is much smaller than the size of them, which means the position of the defects can be acquired accurately by this approach.

  6. A dynamic scanning method based on signal-statistics for scanning electron microscopy.

    PubMed

    Timischl, F

    2014-01-01

    A novel dynamic scanning method for noise reduction in scanning electron microscopy and related applications is presented. The scanning method dynamically adjusts the scanning speed of the electron beam depending on the statistical behavior of the detector signal and gives SEM images with uniform and predefined standard deviation, independent of the signal value itself. In the case of partially saturated images, the proposed method decreases image acquisition time without sacrificing image quality. The effectiveness of the proposed method is shown and compared to the conventional scanning method and median filtering using numerical simulations.

  7. A run-based two-scan labeling algorithm.

    PubMed

    He, Lifeng; Chao, Yuyan; Suzuki, Kenji

    2008-05-01

    We present an efficient run-based two-scan algorithm for labeling connected components in a binary image. Unlike conventional label-equivalence-based algorithms, which resolve label equivalences between provisional labels, our algorithm resolves label equivalences between provisional label sets. At any time, all provisional labels that are assigned to a connected component are combined in a set, and the smallest label is used as the representative label. The corresponding relation of a provisional label and its representative label is recorded in a table. Whenever different connected components are found to be connected, all provisional label sets concerned with these connected components are merged together, and the smallest provisional label is taken as the representative label. When the first scan is finished, all provisional labels that were assigned to each connected component in the given image will have a unique representative label. During the second scan, we need only to replace each provisional label by its representative label. Experimental results on various types of images demonstrate that our algorithm outperforms all conventional labeling algorithms.

  8. Optimization of Designs for Nanotube-based Scanning Probes

    NASA Technical Reports Server (NTRS)

    Harik, V. M.; Gates, T. S.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Optimization of designs for nanotube-based scanning probes, which may be used for high-resolution characterization of nanostructured materials, is examined. Continuum models to analyze the nanotube deformations are proposed to help guide selection of the optimum probe. The limitations on the use of these models that must be accounted for before applying to any design problem are presented. These limitations stem from the underlying assumptions and the expected range of nanotube loading, end conditions, and geometry. Once the limitations are accounted for, the key model parameters along with the appropriate classification of nanotube structures may serve as a basis for the design optimization of nanotube-based probe tips.

  9. Large Aperture Scanning Lidar Based on Holographic Optical Elements

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Miller, David O.; Wilkerson, Thomas D.; Andrus, Ionio; Guerra, David V.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Lidar remote sensing instruments can make a significant contribution to satisfying many of the required measurements of atmospheric and surface parameters for future spaceborne platforms, including topographic altimeters, atmospheric profiles of, wind, humidity, temperature, trace molecules, aerosols, and clouds. It is highly desirable to have wide measurement swaths for rapid coverage rather than just the narrow ribbon of data that is obtained with a nadir only observation. For most applications global coverage is required, and for wind measurements scanning or pointing is required in order to retrieve the full 3-D wind vector from multiple line-of-sight Doppler measurements. Conventional lidar receivers make up a substantial portion of the instrument's size and weight. Wide angle scanning typically requires a large scanning mirror in front of the receiver telescope, or pointing the entire telescope and aft optics assembly, Either of these methods entails the use of large bearings, motors, gearing and their associated electronics. Spaceborne instruments also need reaction wheels to counter the torque applied to the spacecraft by these motions. NASA has developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. NASA has developed two operating lidar systems based on 40 cm diameter HOEs. The first such system, named Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) was a joint development between NASA Goddard Space Flight Center (GSFC) and the University of Maryland College Park. PHASERS is based on a reflection HOE for use at the doubled Nd:YAG laser wavelength of 532 nm and has recently undergone a number of design changes in a collaborative effort between GSFC and Saint Anselm College in New Hampshire. The next step was to develop IR transmission HOEs for use with the Nd:YAG fundamental in the Holographic Airborne

  10. A lower limb exoskeleton control system based on steady state visual evoked potentials

    NASA Astrophysics Data System (ADS)

    Kwak, No-Sang; Müller, Klaus-Robert; Lee, Seong-Whan

    2015-10-01

    Objective. We have developed an asynchronous brain-machine interface (BMI)-based lower limb exoskeleton control system based on steady-state visual evoked potentials (SSVEPs). Approach. By decoding electroencephalography signals in real-time, users are able to walk forward, turn right, turn left, sit, and stand while wearing the exoskeleton. SSVEP stimulation is implemented with a visual stimulation unit, consisting of five light emitting diodes fixed to the exoskeleton. A canonical correlation analysis (CCA) method for the extraction of frequency information associated with the SSVEP was used in combination with k-nearest neighbors. Main results. Overall, 11 healthy subjects participated in the experiment to evaluate performance. To achieve the best classification, CCA was first calibrated in an offline experiment. In the subsequent online experiment, our results exhibit accuracies of 91.3 ± 5.73%, a response time of 3.28 ± 1.82 s, an information transfer rate of 32.9 ± 9.13 bits/min, and a completion time of 1100 ± 154.92 s for the experimental parcour studied. Significance. The ability to achieve such high quality BMI control indicates that an SSVEP-based lower limb exoskeleton for gait assistance is becoming feasible.

  11. Understanding positional cues in salamander limb regeneration: implications for optimizing cell-based regenerative therapies.

    PubMed

    McCusker, Catherine D; Gardiner, David M

    2014-06-01

    Regenerative medicine has reached the point where we are performing clinical trials with stem-cell-derived cell populations in an effort to treat numerous human pathologies. However, many of these efforts have been challenged by the inability of the engrafted populations to properly integrate into the host environment to make a functional biological unit. It is apparent that we must understand the basic biology of tissue integration in order to apply these principles to the development of regenerative therapies in humans. Studying tissue integration in model organisms, where the process of integration between the newly regenerated tissues and the 'old' existing structures can be observed and manipulated, can provide valuable insights. Embryonic and adult cells have a memory of their original position, and this positional information can modify surrounding tissues and drive the formation of new structures. In this Review, we discuss the positional interactions that control the ability of grafted cells to integrate into existing tissues during the process of salamander limb regeneration, and discuss how these insights could explain the integration defects observed in current cell-based regenerative therapies. Additionally, we describe potential molecular tools that can be used to manipulate the positional information in grafted cell populations, and to promote the communication of positional cues in the host environment to facilitate the integration of engrafted cells. Lastly, we explain how studying positional information in current cell-based therapies and in regenerating limbs could provide key insights to improve the integration of cell-based regenerative therapies in the future.

  12. Spot-Scanning-Based Proton Therapy for Extracranial Chordoma

    SciTech Connect

    Staab, Adrian; Rutz, Hans Peter; Ares, Carmen; Timmermann, Beate; Schneider, Ralf; Bolsi, Alessandra; Albertini, Francesca; Lomax, Antony; Goitein, Gudrun; Hug, Eugen

    2011-11-15

    Purpose: To evaluate effectiveness and safety of spot-scanning-based proton-radiotherapy (PT) for extracranial chordomas (ECC). Methods and Material: Between 1999-2006, 40 patients with chordoma of C-, T-, and L-spine and sacrum were treated at Paul Scherrer Institute (PSI) with PT using spot-scanning. Median patient age was 58 years (range, 10-81 years); 63% were male, and 36% were female. Nineteen patients (47%) had gross residual disease (mean 69 cc; range, 13-495 cc) before PT, and 21 patients (53%) had undergone prior titanium-based surgical stabilization (SS) and reconstruction of the axial skeleton. Proton doses were expressed as Gy(RBE). A conversion factor of 1.1 was used to account for higher relative biological effectiveness (RBE) of protons compared with photons. Mean total dose was 72.5 Gy(RBE) [range, 59.4-75.2 Gy(RBE)] delivered at 1.8-2.0 Gy(RBE) dose per fraction. Median follow-up time was 43 months. Results: In 19 patients without surgical stabilization, actuarial local control (LC) rate at 5 years was 100%. LC for patients with gross residual disease but without surgical stabilization was also 100% at 5 years. In contrast, 12 failures occurred in 21 patients with SS, yielding a significantly decreased 5-year LC rate of 30% (p = 0.0003). For the entire cohort, 5-year LC rates were 62%, disease-free survival rates were 57%, and overall survival rates were 80%. Rates were 100% for patients without SS. No other factor, including dosimetric parameters (V95, V80) were predictive for tumor control on univariate analysis. Conclusion: Spot-scanning-based PT at PSI delivered subsequently to function-preserving surgery for tumor debulking, decompression of spinal cord, or biopsy only is safe and highly effective in patients with ECC without major surgical instrumentation even in view of large, unresectable disease.

  13. Markov Jump Linear Systems-Based Position Estimation for Lower Limb Exoskeletons

    PubMed Central

    Nogueira, Samuel L.; Siqueira, Adriano A. G.; Inoue, Roberto S.; Terra, Marco H.

    2014-01-01

    In this paper, we deal with Markov Jump Linear Systems-based filtering applied to robotic rehabilitation. The angular positions of an impedance-controlled exoskeleton, designed to help stroke and spinal cord injured patients during walking rehabilitation, are estimated. Standard position estimate approaches adopt Kalman filters (KF) to improve the performance of inertial measurement units (IMUs) based on individual link configurations. Consequently, for a multi-body system, like a lower limb exoskeleton, the inertial measurements of one link (e.g., the shank) are not taken into account in other link position estimation (e.g., the foot). In this paper, we propose a collective modeling of all inertial sensors attached to the exoskeleton, combining them in a Markovian estimation model in order to get the best information from each sensor. In order to demonstrate the effectiveness of our approach, simulation results regarding a set of human footsteps, with four IMUs and three encoders attached to the lower limb exoskeleton, are presented. A comparative study between the Markovian estimation system and the standard one is performed considering a wide range of parametric uncertainties. PMID:24451469

  14. Learning to throw on a rotating carousel: recalibration based on limb dynamics and projectile kinematics.

    PubMed

    Bruggeman, Hugo; Pick, Herbert L; Rieser, John J

    2005-05-01

    Skilled actions exhibit adjustment in calibration to bring about their goals. The sought-after calibrations change as a function of the environmental situation that stages the actions. In these experiments participants sat on one side of a rotating carousel and threw beanbags underhanded at a target fixed on the opposite side. Logically, aimed throwing in this situation involves adjustment to fit changes in limb dynamics (originating from Coriolis forces) and changes in perceived projectile kinematics (originating from the tangential velocity of thrower and target). We studied whether such adjustment involved one or multiple components of recalibration. An initial experiment showed that exposure to rotation while throwing beanbags produced a robust recalibration in the direction of underhanded throws as manifest in throwing at stationary targets from a stationary position. Following some initial decay this recalibration persisted and approached an asymptote. Subsequent experiments suggested two independent components of recalibration. One is based on limb dynamics and accounts for the initial decay. The other is based on the perceived projectile kinematics and accounts for the stable change in throwing direction. These results raised the question of how multiple components of recalibration of an action are related. We propose that movement components are independent and calibrated separately at different levels in the organization of an action.

  15. Muscle fatigue evaluation of astronaut upper limb based on sEMG and subjective assessment

    NASA Astrophysics Data System (ADS)

    Zu, Xiaoqi; Zhou, Qianxiang; Li, Yun

    2012-07-01

    All movements are driven by muscle contraction, and it is easy to cause muscle fatigue. Evaluation of muscle fatigue is a hot topic in the area of astronaut life support training and rehabilitation. If muscle gets into fatigue condition, it may reduce work efficiency and has an impact on psychological performance. Therefore it is necessary to develop an accurate and usable method on muscle fatigue evaluation of astronaut upper limb. In this study, we developed a method based on surface electromyography (sEMG) and subjective assessment (Borg scale) to evaluate local muscle fatigue. Fifteen healthy young male subjects participated in the experiment. They performed isometric muscle contractions of the upper limb. sEMG of the biceps brachii were recorded during the entire process of isotonic muscle contraction and Borg scales of muscle fatigue were collected in certain times. sEMG were divided into several parts, and then mean energy of each parts were calculated by the one-twelfth band octave method. Equations were derived based on the relationship between the mean energy of sEMG and Borg scale. The results showed that cubic curve could describe the degree of local muscle fatigue, and could be used to evaluate and monitor local muscle fatigue during the entire process.

  16. Electromyography-based analysis of human upper limbs during 45-day head-down bed-rest

    NASA Astrophysics Data System (ADS)

    Fu, Anshuang; Wang, Chunhui; Qi, Hongzhi; Li, Fan; Wang, Zheng; He, Feng; Zhou, Peng; Chen, Shanguang; Ming, Dong

    2016-03-01

    Muscle deconditioning occurs in response to simulated or actual microgravity. In spaceflight, astronauts become monkey-like for mainly using their upper limbs to control the operating system and to complete corresponding tasks. The changes of upper limbs' athletic ability will directly affect astronauts' working performance. This study investigated the variation trend of surface electromyography (sEMG) during prolonged simulated microgravity. Eight healthy males participating in this study performed strict 45-day head-down bed-rest (HDBR). On the 5th day of pre-HDBR, and the 15th, the 30th and the 45th days of HDBR, the subjects performed maximum pushing task and maximum pulling task, and sEMG was collected from upper limbs synchronously. Each subject's maximum volunteer contractions of both the tasks during these days were compared, showing no significant change. However, changes were detected by sEMG-based analysis. It was found that integrated EMG, root mean square, mean frequency, fuzzy entropy of deltoid, and fuzzy entropy of triceps brachii changed significantly when comparing pre-HDBR with HDBR. The variation trend showed a recovery tendency after significant decline, which is inconsistent with the monotonic variation of lower limbs that was proved by previous research. These findings suggest that EMG changes in upper limbs during prolonged simulated microgravity, but has different variation trend from lower limbs.

  17. Artificial Limbs

    MedlinePlus

    ... you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which is ... activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as before.

  18. Transcranial direct current stimulation and EEG-based motor imagery BCI for upper limb stroke rehabilitation.

    PubMed

    Ang, Kai Keng; Guan, Cuntai; Phua, Kok Soon; Wang, Chuanchu; Teh, Irvin; Chen, Chang Wu; Chew, Effie

    2012-01-01

    Clinical studies had shown that EEG-based motor imagery Brain-Computer Interface (MI-BCI) combined with robotic feedback is effective in upper limb stroke rehabilitation, and transcranial Direct Current Stimulation (tDCS) combined with other rehabilitation techniques further enhanced the facilitating effect of tDCS. This motivated the current clinical study to investigate the effects of combining tDCS with MI-BCI and robotic feedback compared to sham-tDCS for upper limb stroke rehabilitation. The stroke patients recruited were randomized to receive 20 minutes of tDCS or sham-tDCS prior to 10 sessions of 1-hour MI-BCI with robotic feedback for 2 weeks. The online accuracies of detecting motor imagery from idle condition were assessed and offline accuracies of classifying motor imagery from background rest condition were assessed from the EEG of the evaluation and therapy parts of the 10 rehabilitation sessions respectively. The results showed no evident differences between the online accuracies on the evaluation part from both groups, but the offline analysis on the therapy part yielded higher averaged accuracies for subjects who received tDCS (n=3) compared to sham-tDCS (n=2). The results suggest towards tDCS effect in modulating motor imagery in stroke, but a more conclusive result can be drawn when more data are collected in the ongoing study.

  19. Are determinants for new and persistent upper limb pain different? An analysis based on anatomical sites

    PubMed Central

    Vargas-Prada, Sergio; Serra, Consol; Coggon, David; Martínez, José Miguel; Ntani, Georgia; Delclos, George; Palmer, Keith T.; Benavides, Fernando G.

    2015-01-01

    BACKGROUND Only few longitudinal studies have explored separately predictors of pain incidence and persistence. OBJECTIVE To investigate whether biological, lifestyle, occupational and psychological risk factors for the development of new episodes of upper limb pain (ULP) differ from those for its persistence. METHODS 1105 Spanish nurses and office workers were asked at baseline about biological, lifestyle, occupational and psychological risk factors and pain in the past month at six anatomical sites in the upper limb (left and right shoulder, elbow and wrist/hand). At follow up, 12 months later, pain in the past month was again ascertained. Analysis was based on anatomical sites clustered by person. Associations were assessed by multilevel logistic regression models. RESULTS 971 participants (87.9%) completed follow-up. Job dissatisfaction and older age carried higher risk of new ULP. Somatising tendency (OR 2.2, 95%CI 1.6-3.1) was the strongest predictor of new ULP, with a risk estimate which differed significantly from that for the same exposure and persistence of ULP. Having adverse beliefs about the work-relatedness of ULP carried a significantly reduced risk for persistence of ULP. CONCLUSION Our study provides only limited evidence that risk factors predicting new ULP differ from those predicting its persistence. PMID:26409386

  20. Reliability of lower limb alignment measures using an established landmark-based method with a customized computer software program.

    PubMed

    Sled, Elizabeth A; Sheehy, Lisa M; Felson, David T; Costigan, Patrick A; Lam, Miu; Cooke, T Derek V

    2011-01-01

    The objective of the study was to evaluate the reliability of frontal plane lower limb alignment measures using a landmark-based method by (1) comparing inter- and intra-reader reliability between measurements of alignment obtained manually with those using a computer program, and (2) determining inter- and intra-reader reliability of computer-assisted alignment measures from full-limb radiographs. An established method for measuring alignment was used, involving selection of 10 femoral and tibial bone landmarks. (1) To compare manual and computer methods, we used digital images and matching paper copies of five alignment patterns simulating healthy and malaligned limbs drawn using AutoCAD. Seven readers were trained in each system. Paper copies were measured manually and repeat measurements were performed daily for 3 days, followed by a similar routine with the digital images using the computer. (2) To examine the reliability of computer-assisted measures from full-limb radiographs, 100 images (200 limbs) were selected as a random sample from 1,500 full-limb digital radiographs which were part of the Multicenter Osteoarthritis Study. Three trained readers used the software program to measure alignment twice from the batch of 100 images, with two or more weeks between batch handling. Manual and computer measures of alignment showed excellent agreement (intraclass correlations [ICCs] 0.977-0.999 for computer analysis; 0.820-0.995 for manual measures). The computer program applied to full-limb radiographs produced alignment measurements with high inter- and intra-reader reliability (ICCs 0.839-0.998). In conclusion, alignment measures using a bone landmark-based approach and a computer program were highly reliable between multiple readers.

  1. Land-Based Mobile Laser Scanning Systems: a Review

    NASA Astrophysics Data System (ADS)

    Puente, I.; González-Jorge, H.; Arias, P.; Armesto, J.

    2011-09-01

    Mobile mapping has been using various photogrammetric techniques for many years. In recent years, there has been an increase in the number of mobile mapping systems using laser scanners available in the market, partially because of the improvement in GNSS/INS performance for direct georeferencing. In this article, some of the most important land-based mobile laser scanning (MLS) systems are reviewed. Firstly, the main characteristics of MLS systems vs. airborne (ALS) and terrestrial laser scanning (TLS) systems are compared. Secondly, a short overview of the mobile mapping technology is also provided so that the reader can fully grasp the complexity and operation of these devices. As we put forward in this paper, a comparison of different systems is briefly carried out regarding specifications provided by the manufacturers. Focuses on the current research are also addressed with emphasis on the practical applications of these systems. Most of them have been utilized for data collection on road infrastructures or building façades. This article shows that MLS technology is nowadays well established and proven, since the demand has grown to the point that there are several systems suppliers offering their products to satisfy this particular market.

  2. Upper Limb Posture Estimation in Robotic and Virtual Reality-Based Rehabilitation

    PubMed Central

    Cortés, Camilo; Ardanza, Aitor; Molina-Rueda, F.; Cuesta-Gómez, A.; Ruiz, Oscar E.

    2014-01-01

    New motor rehabilitation therapies include virtual reality (VR) and robotic technologies. In limb rehabilitation, limb posture is required to (1) provide a limb realistic representation in VR games and (2) assess the patient improvement. When exoskeleton devices are used in the therapy, the measurements of their joint angles cannot be directly used to represent the posture of the patient limb, since the human and exoskeleton kinematic models differ. In response to this shortcoming, we propose a method to estimate the posture of the human limb attached to the exoskeleton. We use the exoskeleton joint angles measurements and the constraints of the exoskeleton on the limb to estimate the human limb joints angles. This paper presents (a) the mathematical formulation and solution to the problem, (b) the implementation of the proposed solution on a commercial exoskeleton system for the upper limb rehabilitation, (c) its integration into a rehabilitation VR game platform, and (d) the quantitative assessment of the method during elbow and wrist analytic training. Results show that this method properly estimates the limb posture to (i) animate avatars that represent the patient in VR games and (ii) obtain kinematic data for the patient assessment during elbow and wrist analytic rehabilitation. PMID:25110698

  3. Planar metamaterial-based beam-scanning broadband microwave antenna

    SciTech Connect

    Dhouibi, Abdallah; Burokur, Shah Nawaz Lustrac, André de

    2014-05-21

    The broadband directive emission from the use of waveguided metamaterials is numerically and experimentally reported. The metamaterials, which are composed of non-resonant circular complementary closed ring structures printed on a dielectric substrate, are designed to obey the refractive index of a Luneburg lens. An arc array of planar radiating slot antennas placed at the periphery of the lens is used as wave launchers. A prototype of the lens associated with the feed structures has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, far-field radiation patterns have been measured. Furthermore, this metamaterial-based lens can be used to achieve beam-scanning with a coverage of up to 120 °. Far-field measurements agree qualitatively with calculated near-field distributions.

  4. Cooperative Environment Scans Based on a Multi-Robot System

    PubMed Central

    Kwon, Ji-Wook

    2015-01-01

    This paper proposes a cooperative environment scan system (CESS) using multiple robots, where each robot has low-cost range finders and low processing power. To organize and maintain the CESS, a base robot monitors the positions of the child robots, controls them, and builds a map of the unknown environment, while the child robots with low performance range finders provide obstacle information. Even though each child robot provides approximated and limited information of the obstacles, CESS replaces the single LRF, which has a high cost, because much of the information is acquired and accumulated by a number of the child robots. Moreover, the proposed CESS extends the measurement boundaries and detects obstacles hidden behind others. To show the performance of the proposed system and compare this with the numerical models of the commercialized 2D and 3D laser scanners, simulation results are included. PMID:25789491

  5. Planar metamaterial-based beam-scanning broadband microwave antenna

    NASA Astrophysics Data System (ADS)

    Dhouibi, Abdallah; Burokur, Shah Nawaz; de Lustrac, André

    2014-05-01

    The broadband directive emission from the use of waveguided metamaterials is numerically and experimentally reported. The metamaterials, which are composed of non-resonant circular complementary closed ring structures printed on a dielectric substrate, are designed to obey the refractive index of a Luneburg lens. An arc array of planar radiating slot antennas placed at the periphery of the lens is used as wave launchers. A prototype of the lens associated with the feed structures has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, far-field radiation patterns have been measured. Furthermore, this metamaterial-based lens can be used to achieve beam-scanning with a coverage of up to 120 °. Far-field measurements agree qualitatively with calculated near-field distributions.

  6. Surface skeleton generation based on 360-degree profile scan

    NASA Astrophysics Data System (ADS)

    Chen, Lujie; Sass, Lawrence; Sung, Woong Ki; Noel, Vernelle

    2013-05-01

    A rapid prototyping method is invented, which works on a specific data structure produced by an optical metrology technique: 360-degree surface profile scanning. A computer algorithm takes an object profile data, restructure the format, generate horizontal and vertical ribs, lay out the ribs on a 2D canvas and output the geometries to a file format compatible with laser cutters. A laser cutting machine is subsequently used to cut all the ribs from sheet materials. Then, the ribs are manually assembled based on computer-generated assembly codes. Through this process, the original object's 3D surface can be prototyped rapidly at an arbitrary scale, which may well exceed the working dimension of the laser cutter.

  7. FACS-based Satellite Cell Isolation From Mouse Hind Limb Muscles.

    PubMed

    Gromova, Anastasia; Tierney, Matthew T; Sacco, Alessandra

    2015-08-20

    Fluorescence Activated Cell Sorting (FACS) is a sensitive and accurate method for purifying satellite cells, or muscle stem cells, from adult mouse skeletal muscle (Liu et al., 2013; Sacco et al., 2008; Tierney et al., 2014). Mechanical and enzymatic digestion of hind limb muscles releases mononuclear muscle cells into suspension. This protocol employs fractionation strategies to deplete cells expressing the cell surface markers CD45, CD31, CD11b and Ly-6A/E-Sca1, both by magnetic separation and FACS-based exclusion, and positively select for cells expressing a7-integrin and CD34. This enables the researcher to successfully enrich satellite cells that uniformly express the paired-box transcription factor Pax7 and are capable of long-term self-renewal, skeletal muscle repair and muscle stem cell pool repopulation.

  8. [Study on the control of dynamic artificial limb ankle based on central pattern generator].

    PubMed

    Guo, Xin; Xu, Caiyu; Li, Mingyue; Su, Longtao

    2014-12-01

    In order to obtain the normal gait for the prosthesis-carrier with the change of external environment and gait, we designed a model of dynamic ankle prosthesis and control system and introduced the strategy of central pattern generator (CPG) about the moving trail of dynamic ankle prosthesis. The dynamic parts, which are incorporated in the model of dynamic ankle prosthesis, provide power in order to have anthropic function and character. The tool of Matlab/simulink was used to simulate the strategy. The simulation results showed that the strategy of CPG learn- ing control in this study was effective and could track the reference trail rapidly and fit the moving trail of a person's normal limb. It can make the prosthetic timely regulation and action, enhance the prosthetic intelligence. It has im- portant practical value for intelligent prosthesis development based on this analysis of technology.

  9. Three phase bone scan interpretation based upon vascular endothelial response

    PubMed Central

    Kumar, Kush

    2015-01-01

    Objectives: A new method of interpretation of Three Phase Bone Scan (TPBS) scan based upon the normal physiological vascular endothelial related response. Materials and Methods: Fifty cases of TPBS were evaluated. Thirteen were normal. In remaining 37 positive studies, 20 showed localized hyperemic response. All localized hyperemic responses except one with vascular endothelial dysfunction were without infection (95.0%). Infection could be ruled out in absence of generalized massive flow and pool response. All 17 cases with generalized massive hyperemic response had infection, consistent with infection or CRPS/RSD. Micro-bacterial or histological confirmation of infection was obtained in 11 cases. All 11 cases with confirmed infection showed generalized massive hyperemic response (100.0%). Two were CRPS/RSD and 2 cases were of cellulitis (100.0%). Among remaining 2, one refused surgery and other was lost to follow-up. Additionally, 20 published cases in the literature of osteomyelitis were also analyzed. Nineteen cases of bone and joint infection, (osteomyelitis/arthritis/cellulitis) except one with endothelial dysfunction showed generalized massive increased flow and pool response (95.0%). All published cases of osteomyelitis in the literature showed generalized massive hyperemic response (100.0%). Results: The data clearly indicated that 100% of the cases of bone infection (osteomyelitis/arthritis/cellulitis) and cases of CRPS/RSD showed generalized massive flow and pool pattern. Infection could be ruled out in absence of generalized massive flow and pool response. All 100% published cases of osteomyelitis in the literature showed positive vascular endothelial response. Conclusion: By incorporating the concept of vascular endothelial related response causing massive vasodilatation in infection, the interpretation of the TPBS can be more précised as it is based upon the normal physiology. Larger studies are recommended. PMID:25829726

  10. FocalScan: Scanning for altered genes in cancer based on coordinated DNA and RNA change

    PubMed Central

    Karlsson, Joakim; Larsson, Erik

    2016-01-01

    Somatic genomic copy-number alterations can lead to transcriptional activation or inactivation of tumor driver or suppressor genes, contributing to the malignant properties of cancer cells. Selection for such events may manifest as recurrent amplifications or deletions of size-limited (focal) regions. While methods have been developed to identify such focal regions, finding the exact targeted genes remains a challenge. Algorithms are also available that integrate copy number and RNA expression data, to aid in identifying individual targeted genes, but specificity is lacking. Here, we describe FocalScan, a tool designed to simultaneously uncover patterns of focal copy number alteration and coordinated expression change, thus combining both principles. The method outputs a ranking of tentative cancer drivers or suppressors. FocalScan works with RNA-seq data, and unlike other tools it can scan the genome unaided by a gene annotation, enabling identification of novel putatively functional elements including lncRNAs. Application on a breast cancer data set suggests considerably better performance than other DNA/RNA integration tools. PMID:27474725

  11. Comparison of models to identify lame cows based on gait and lesion scores, and limb movement variables.

    PubMed

    Rajkondawar, P G; Liu, M; Dyer, R M; Neerchal, N K; Tasch, U; Lefcourt, A M; Erez, B; Varner, M A

    2006-11-01

    Bovine lameness results in pain and suffering in cattle and economic loss for producers. A system for automatically detecting lame cows was developed recently that measures vertical force components attributable to individual limbs. These measurements can be used to calculate a number of limb movement variables. The objective of this investigation was to explore whether gait scores, lesion scores, or combined gait and lesion scores were more effectively captured by a set of 5 limb movement variables. A set of 700 hind limb examinations was used to create gait-based, lesion-based, and combined (gait- and lesion-based) models. Logistic regression models were constructed using 1, 2, or 3 d of measurements. Resulting models were tested on cows not used in modeling. The accuracy of lesion-score models was superior to that of gait-score models; lesion-based models generated greater values of areas under the receiving operating characteristic curves (range 0.75 to 0.84) and lower mean-squared errors (0.13 to 0.16) compared with corresponding values for the gait-based models (0.63 to 0.73 and 0.26 to 0.31 for receiving operating characteristic and mean-squared errors, respectively). These results indicate that further model development and investigation could generate automated and objective methods of lameness detection in dairy cattle.

  12. Kinect One-based biomechanical assessment of upper-limb performance compared to clinical scales in post-stroke patients.

    PubMed

    Scano, Alessandro; Caimmi, Marco; Chiavenna, Andrea; Malosio, Matteo; Tosatti, Lorenzo Molinari

    2015-08-01

    This paper presents a Kinect One sensor-based protocol for the evaluation of the motor-performances of the upper limb of neurological patients during rehabilitative sessions. The assessment provides evaluations of kinematic, dynamic, motor and postural control variables. A pilot study was conducted on three post-stroke neurological patients, comparing Kinect-One biomechanical assessment with the outcomes of some of the most common clinical scales for the evaluation of the upper-limb functionality. Preliminary results indicate coherency between the clinical and instrumental evaluation. Moreover, the Kinect-One assessment seems to provide some complementary quantitative information, consistently integrating the clinical assessment.

  13. Comparison of stratospheric NO2 profiles above Kiruna, Sweden retrieved from ground-based zenith sky DOAS measurements, SAOZ balloon measurements and SCIAMACHY limb observations

    NASA Astrophysics Data System (ADS)

    Gu, Myojeong; Enell, Carl-Fredrik; Hendrick, François; Pukite, Janis; Van Roozendael, Michel; Platt, Ulrich; Raffalski, Uwe; Wagner, Thomas

    2015-04-01

    Stratospheric NO2 not only destroys ozone but acts as a buffer against halogen catalyzed ozone loss by converting halogen species into stable nitrates. These two roles of stratospheric NO2 depend on the altitude. Hence, the objective of this study is to investigate the vertical distribution of stratospheric NO2. We compare the NO2 profiles derived from the zenith sky DOAS with those obtained from, SAOZ balloon measurements and satellite limb observations. Vertical profiles of stratospheric NO2 are retrieved from ground-based zenith sky DOAS observations operated at Kiruna, Sweden (68.84°N, 20.41°E) since 1996. To determine the profile of stratospheric NO2 measured from ground-based zenith sky DOAS, we apply the Optimal Estimation Method (OEM) to retrieval of vertical profiles of stratospheric NO2 which has been developed by IASB-BIRA. The basic principle behind this profiling approach is the dependence of the mean scattering height on solar zenith angle (SZA). We compare the retrieved profiles to two additional datasets of stratospheric NO2 profile. The first one is derived from satellite limb observations by SCIAMACHY (Scanning Imaging Absorption spectrometer for Atmospheric CHartographY) on EnviSAT. The second is derived from the SAOZ balloon measurements (using a UV/Visible spectrometer) performed at Kiruna in Sweden.

  14. Ambulatory activity classification with dendogram-based support vector machine: Application in lower-limb active exoskeleton.

    PubMed

    Mazumder, Oishee; Kundu, Ananda Sankar; Lenka, Prasanna Kumar; Bhaumik, Subhasis

    2016-10-01

    Ambulatory activity classification is an active area of research for controlling and monitoring state initiation, termination, and transition in mobility assistive devices such as lower-limb exoskeletons. State transition of lower-limb exoskeletons reported thus far are achieved mostly through the use of manual switches or state machine-based logic. In this paper, we propose a postural activity classifier using a 'dendogram-based support vector machine' (DSVM) which can be used to control a lower-limb exoskeleton. A pressure sensor-based wearable insole and two six-axis inertial measurement units (IMU) have been used for recognising two static and seven dynamic postural activities: sit, stand, and sit-to-stand, stand-to-sit, level walk, fast walk, slope walk, stair ascent and stair descent. Most of the ambulatory activities are periodic in nature and have unique patterns of response. The proposed classification algorithm involves the recognition of activity patterns on the basis of the periodic shape of trajectories. Polynomial coefficients extracted from the hip angle trajectory and the centre-of-pressure (CoP) trajectory during an activity cycle are used as features to classify dynamic activities. The novelty of this paper lies in finding suitable instrumentation, developing post-processing techniques, and selecting shape-based features for ambulatory activity classification. The proposed activity classifier is used to identify the activity states of a lower-limb exoskeleton. The DSVM classifier algorithm achieved an overall classification accuracy of 95.2%.

  15. Optimal alignment of mirror based pentaprisms for scanning deflectometric devices

    SciTech Connect

    Barber, Samuel K.; Geckeler, Ralf D.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Buchheim, Jana; Siewert, Frank; Zeschke, Thomas

    2011-03-04

    In the recent work [Proc. of SPIE 7801, 7801-2/1-12 (2010), Opt. Eng. 50(5) (2011), in press], we have reported on improvement of the Developmental Long Trace Profiler (DLTP), a slope measuring profiler available at the Advanced Light Source Optical Metrology Laboratory, achieved by replacing the bulk pentaprism with a mirror based pentaprism (MBPP). An original experimental procedure for optimal mutual alignment of the MBPP mirrors has been suggested and verified with numerical ray tracing simulations. It has been experimentally shown that the optimally aligned MBPP allows the elimination of systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of the bulk pentaprism. In the present article, we provide the analytical derivation and verification of easily executed optimal alignment algorithms for two different designs of mirror based pentaprisms. We also provide an analytical description for the mechanism for reduction of the systematic errors introduced by a typical high quality bulk pentaprism. It is also shown that residual misalignments of an MBPP introduce entirely negligible systematic errors in surface slope measurements with scanning deflectometric devices.

  16. An accelerometry-based study of lower and upper limb tremor in Parkinson's disease.

    PubMed

    Scanlon, Blake K; Levin, Bonnie E; Nation, Daniel A; Katzen, Heather L; Guevara-Salcedo, Alexandra; Singer, Carlos; Papapetropoulos, Spiridon

    2013-06-01

    Over the past two decades, several studies have aimed to quantify the kinetic properties of tremor with primary focus on the upper limbs. However, there is a lack of investigation into the properties of tremor in the lower limbs. The objective of this preliminary study was to investigate the properties of oscillatory movement, at rest and in posture, in both the upper and lower limbs of Parkinson's disease (PD) patients with clinically undetectable to modest rest/postural tremor and healthy controls. PD patients (N = 16) and controls (N = 8) were examined clinically by a movement disorders specialist and oscillatory movements in all four extremities were evaluated using a portable biaxial accelerometer. While tremor intensity and frequency did not differ between groups, the intraindividual variability of rest and postural tremor frequency in the dexterity-dominant lower limb was lower in people living with PD than in healthy adults. Additionally, rest tremor frequency was discrepant between upper and lower limbs in PD. Our work introduces the possibility that minute variations in lower limb movements, which are imperceptible upon expert clinical exam, can be used to differentiate a diseased sample from a healthy one. These preliminary findings suggest that additional work using objective tremor measurement may improve our understanding of lower limb motor dysfunction in PD and lead to the refinement of current, and the development of new, metrics to enhance early diagnosis, differential diagnosis, and symptom quantification.

  17. Realization of Intelligent Measurement and Control System for Limb Rehabilitation Based on PLC and Touch Screen

    NASA Astrophysics Data System (ADS)

    Liu, Xiangquan

    According to the treatment needs of patients with limb movement disorder, on the basis of the limb rehabilitative training prototype, function of measure and control system are analyzed, design of system hardware and software is completed. The touch screen which is adopt as host computer and man-machine interaction window is responsible for sending commands and training information display; The PLC which is adopt as slave computer is responsible for receiving control command from touch screen, collecting the sensor data, regulating torque and speed of motor by analog output according to the different training mode, realizing ultimately active and passive training for limb rehabilitation therapy.

  18. High resolution digital holography based on the point source scanning

    NASA Astrophysics Data System (ADS)

    Wang, Minchao; Wang, Dayong; Rong, Lu; Wang, Yunxin; Wang, Fengpeng; Lin, Qiaowen

    2016-10-01

    Digital holographic microscopy has been widely used for the imaging of micro-objects and biological samples. Lensless in-line digital holographic microscopy is capable of wide field-of-view imaging. However the spatial resolution of the reconstructed images is limited by the pixel size of the detector. The relative position shift between the sample and the detector can effectively improve the resolution in the traditional sub-pixel shifting method, but it requires a high precision of translation stage. To overcome this problem, we propose a method based on the point source scanning to realize sub-pixel shifting. High precision sub-pixel shifting is achieved easily by using the geometric between point source and detector. Through moving the point source, multiple holograms with sub-pixel shifts are captured. These holograms are merged together to obtained a high resolution hologram by a synthesizing algorithm. Then, the high resolution reconstructed image of the object can be obtained by the angular spectrum algorithm. The feasibility of the proposed method is demonstrated by simulation and experiments. A USAF resolution test target was used as the object. Compared with the traditional digital holography, a higher resolution reconstructed image is obtained by our method. The proposed method has the advantages of simple recording setup and lower precision requirement of the translation stage. It can achieve the wide field-of-view and high resolution imaging.

  19. MEMS segmented-based adaptive optics scanning laser ophthalmoscope

    PubMed Central

    Manzanera, Silvestre; Helmbrecht, Michael A.; Kempf, Carl J.; Roorda, Austin

    2011-01-01

    The performance of a MEMS (micro-electro-mechanical-system) segmented deformable mirror was evaluated in an adaptive optics (AO) scanning laser ophthalmoscope. The tested AO mirror (Iris AO, Inc, Berkeley, CA) is composed of 37 hexagonal segments that allow piston/tip/tilt motion up to 5 μm stroke and ±5 mrad angle over a 3.5 mm optical aperture. The control system that implements the closed-loop operation employs a 1:1 matched 37-lenslet Shack-Hartmann wavefront sensor whose measurements are used to apply modal corrections to the deformable mirror. After a preliminary evaluation of the AO mirror optical performance, retinal images from 4 normal subjects over a 0.9°x0.9° field size were acquired through a 6.4 mm ocular pupil, showing resolved retinal features at the cellular level. Cone photoreceptors were observed as close as 0.25 degrees from the foveal center. In general, the quality of these images is comparable to that obtained using deformable mirrors based on different technologies. PMID:21559132

  20. Dissecting enzyme function with microfluidic-based deep mutational scanning

    PubMed Central

    Romero, Philip A.; Tran, Tuan M.; Abate, Adam R.

    2015-01-01

    Natural enzymes are incredibly proficient catalysts, but engineering them to have new or improved functions is challenging due to the complexity of how an enzyme’s sequence relates to its biochemical properties. Here, we present an ultrahigh-throughput method for mapping enzyme sequence–function relationships that combines droplet microfluidic screening with next-generation DNA sequencing. We apply our method to map the activity of millions of glycosidase sequence variants. Microfluidic-based deep mutational scanning provides a comprehensive and unbiased view of the enzyme function landscape. The mapping displays expected patterns of mutational tolerance and a strong correspondence to sequence variation within the enzyme family, but also reveals previously unreported sites that are crucial for glycosidase function. We modified the screening protocol to include a high-temperature incubation step, and the resulting thermotolerance landscape allowed the discovery of mutations that enhance enzyme thermostability. Droplet microfluidics provides a general platform for enzyme screening that, when combined with DNA-sequencing technologies, enables high-throughput mapping of enzyme sequence space. PMID:26040002

  1. Nanoscale ferroelectric information storage based on scanning nonlinear dielectric microscopy.

    PubMed

    Cho, Yasuo

    2007-01-01

    An investigation of ultrahigh-density ferroelectric data storage based on scanning nonlinear dielectric microscopy (SNDM) is described. For the purpose of obtaining fundamental knowledge on high-density ferroelectric data storage, several experiments on nanodomain formation in a lithium tantalate (LiTaO3) single crystal were conducted. Through domain engineering, a domain dot array with an areal density of 1.5 Tbit/inch2 was formed on congruent LiTaO3 (CLT). Sub-nanosecond (500 psec) domain switching speed also has been achieved. Next, actual information storage is demonstrated at a density of 1 Tbit/inch2. Finally, it is described that application of a very small dc offset voltage is very effective in accelerating the domain switching speed and in stabilizing the reversed nano-domain dots. Applying this offset application technique, we formed a smallest artificial nano-domain single dot of 5.1 nm in diameter and artificial nano-domain dot-array with a memory density of 10.1 Tbit/inch2 and a bit spacing of 8.0 nm, representing the highest memory density for rewritable data storage reported to date.

  2. Laser-scanning Doppler photoacoustic microscopy based on temporal correlation

    NASA Astrophysics Data System (ADS)

    Song, Wei; Liu, Wenzhong; Zhang, Hao F.

    2013-05-01

    We present a methodology to measure absolute flow velocity using laser-scanning photoacoustic microscopy. To obtain the Doppler angle, the angle between ultrasonic detection axis and flow direction, we extracted the distances between the transducer and three adjacent scanning points along the flow and repeatedly applied the law of cosines. To measure flow velocity along the ultrasonic detection axis, we calculated the time shift between two consecutive photoacoustic waves at the same scanning point, then converted the time shift to velocity according to the sound velocity and time interval between two laser illuminations. We verified our method by imaging flow phantoms.

  3. Evidence-based chronic ulcer care and lower limb outcomes among Pacific Northwest veterans.

    PubMed

    Karavan, Mahsa; Olerud, John; Bouldin, Erin; Taylor, Leslie; Reiber, Gayle E

    2015-09-01

    Evidence-based ulcer care guidelines detail optimal components of care for treatment of ulcers of different etiologies. We investigated the impact of providing specific evidence-based ulcer treatment components on healing outcomes for lower limb ulcers (LLU) among veterans in the Pacific Northwest. Components of evidence-based ulcer care for venous, arterial, diabetic foot ulcers/neuropathic ulcers were abstracted from medical records. The outcome was ulcer healing. Our analysis assessed the relationship between evidence-based ulcer care by etiology, components of care provided, and healing, while accounting for veteran characteristics. A minority of veterans in all three ulcer-etiology groups received the recommended components of evidence-based care in at least 80% of visits. The likelihood of healing improved when assessment for edema and infection were performed on at least 80% of visits (hazard ratio [HR] = 3.20, p = 0.009 and HR = 3.54, p = 0.006, respectively) in patients with venous ulcers. There was no significant association between frequency of care components provided and healing among patients with arterial ulcers. Among patients with diabetic/neuropathic ulcers, the chance of healing increased 2.5-fold when debridement was performed at 80% of visits (p = 0.03), and doubled when ischemia was assessed at the first visit (p = 0.045). Veterans in the Pacific Northwest did not uniformly receive evidence-based ulcer care. Not all evidence-based ulcer care components were significantly associated with healing. At a minimum, clinicians need to address components of ulcer care associated with improved ulcer healing.

  4. MEMS-based high speed scanning probe microscopy.

    PubMed

    Disseldorp, E C M; Tabak, F C; Katan, A J; Hesselberth, M B S; Oosterkamp, T H; Frenken, J W M; van Spengen, W M

    2010-04-01

    The high speed performance of a scanning probe microscope (SPM) is improved if a microelectromechanical systems (MEMS) device is employed for the out-of-plane scanning motion. We have carried out experiments with MEMS high-speed z-scanners (189 kHz fundamental resonance frequency) in both atomic force microscope and scanning tunneling microscope modes. The experiments show that with the current MEMS z-scanner, lateral tip speeds of 5 mm/s can be achieved with full feedback on surfaces with significant roughness. The improvement in scan speed, obtained with MEMS scanners, increases the possibilities for SPM observations of dynamic processes. Even higher speed MEMS scanners with fundamental resonance frequencies in excess of a megahertz are currently under development.

  5. Pencil Beam Scanning System Based On A Cyclotron

    SciTech Connect

    Tachikawa, Toshiki; Nonaka, Hideki; Kumata, Yukio; Nishio, Teiji; Ogino, Takashi

    2011-06-01

    Sumitomo Heavy Industries, Ltd. (SHI) has developed a new pencil beam scanning system (PBS) for proton therapy in collaboration with National Cancer Center Hospital East (NCCHE). Taking advantage of the continuous beam from the cyclotron P235, the line scanning method is employed in order to realize continuous irradiation with high dose rate. 3D uniform and sphere field was irradiated and compared with the simulation.

  6. Limb Loss

    MedlinePlus

    ... limb. Learning how to use it takes time. Physical therapy can help you adapt. Recovery from the loss of a limb can be hard. Sadness, anger, and frustration are common. If you are having a tough time, talk to your doctor. Treatment with medicine or counseling can help.

  7. Observational Verification of the Limb-Darkening Law Based on Kepler Data

    NASA Astrophysics Data System (ADS)

    Zola, S.; Baran, A.; Debski, B.; Jableka, D.

    2015-07-01

    We present preliminary results obtained from modeling of light curves of a sample of contact binaries observed by the Kepler spacecraft. Our study was aimed at verifying which of the three most commonly used limb-darkening formulations fits the high quality Kepler data the best. We limited our work to twelve binary systems showing flat-bottomed minima, and we found that for ten of them the square root limb-darkening law led to the best fits.

  8. [Remote intelligent Brunnstrom assessment system for upper limb rehabilitation for post-stroke based on extreme learning machine].

    PubMed

    Wang, Yue; Yu, Lei; Fu, Jianming; Fang, Qiang

    2014-04-01

    In order to realize an individualized and specialized rehabilitation assessment of remoteness and intelligence, we set up a remote intelligent assessment system of upper limb movement function of post-stroke patients during rehabilitation. By using the remote rehabilitation training sensors and client data sampling software, we collected and uploaded the gesture data from a patient's forearm and upper arm during rehabilitation training to database of the server. Then a remote intelligent assessment system, which had been developed based on the extreme learning machine (ELM) algorithm and Brunnstrom stage assessment standard, was used to evaluate the gesture data. To evaluate the reliability of the proposed method, a group of 23 stroke patients, whose upper limb movement functions were in different recovery stages, and 4 healthy people, whose upper limb movement functions were normal, were recruited to finish the same training task. The results showed that, compared to that of the experienced rehabilitation expert who used the Brunnstrom stage standard table, the accuracy of the proposed remote Brunnstrom intelligent assessment system can reach a higher level, as 92.1%. The practical effects of surgery have proved that the proposed system could realize the intelligent assessment of upper limb movement function of post-stroke patients remotely, and it could also make the rehabilitation of the post-stroke patients at home or in a community care center possible.

  9. Multiunit Activity-Based Real-Time Limb-State Estimation from Dorsal Root Ganglion Recordings

    PubMed Central

    Han, Sungmin; Chu, Jun-Uk; Kim, Hyungmin; Park, Jong Woong; Youn, Inchan

    2017-01-01

    Proprioceptive afferent activities could be useful for providing sensory feedback signals for closed-loop control during functional electrical stimulation (FES). However, most previous studies have used the single-unit activity of individual neurons to extract sensory information from proprioceptive afferents. This study proposes a new decoding method to estimate ankle and knee joint angles using multiunit activity data. Proprioceptive afferent signals were recorded from a dorsal root ganglion with a single-shank microelectrode during passive movements of the ankle and knee joints, and joint angles were measured as kinematic data. The mean absolute value (MAV) was extracted from the multiunit activity data, and a dynamically driven recurrent neural network (DDRNN) was used to estimate ankle and knee joint angles. The multiunit activity-based MAV feature was sufficiently informative to estimate limb states, and the DDRNN showed a better decoding performance than conventional linear estimators. In addition, processing time delay satisfied real-time constraints. These results demonstrated that the proposed method could be applicable for providing real-time sensory feedback signals in closed-loop FES systems. PMID:28276474

  10. Fluorescence detection in capillary arrays based on galvanometer step scanning.

    PubMed

    Xue, G; Yeung, E S

    2001-10-01

    A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluoresceins is 3 x 10(-11) M (S/N = 3) for 5 mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  11. Ta Keo Temple Reconstruction Based on Terrestrial Laser Scanning Technology

    NASA Astrophysics Data System (ADS)

    Xi, X.; Wang, C.; Wan, Y. P.; Khuon, K. N.

    2015-08-01

    Ta Keo temple is one of the very famous temple complex of Angkor Wat in northwestern Cambodia. It has been suffering massive collapse and other serious damages in recent years. Nowadays, Terrestrial Laser Scanning(TLS) technology is considered as a wellestablished resource for heritage documentation and protection (Lerma et al, 2008; Reshetyuk, 2009). This paper used TLS to reconstruct Ta Keo Temple. Firstly, we acquired 71 scanning stations of points cloud data with high density and high accuracy, and over one thousand images with high spatial resolution about the temple. Secondly, the raw points cloud data were denoised, reduced and managed efficiently, and registrated using an adjusted ICP algorithm. Thirdly, a triangulation method was used to model most objects. At last, we mapped the texture data into the digital model and a 3-D model of Ta Keo with high accuracy was achieved. The authors focus on large object reconstruction by TLS technology, and pay much attention to the scanning design, multi-station data and the whole project's data registration, and texture mapping and so on. The research result will be useful for Ta Keo restoration, reconstruction and protection. Also, it is a good reference source for large complex buildings reconstruction when using terrestrial laser scanning technology.

  12. SCAN-based hybrid and double-hybrid density functionals from models without fitted parameters

    NASA Astrophysics Data System (ADS)

    Hui, Kerwin; Chai, Jeng-Da

    2016-01-01

    By incorporating the nonempirical strongly constrained and appropriately normed (SCAN) semilocal density functional [J. Sun, A. Ruzsinszky, and J. P. Perdew, Phys. Rev. Lett. 115, 036402 (2015)] in the underlying expression of four existing hybrid and double-hybrid models, we propose one hybrid (SCAN0) and three double-hybrid (SCAN0-DH, SCAN-QIDH, and SCAN0-2) density functionals, which are free from any fitted parameters. The SCAN-based double-hybrid functionals consistently outperform their parent SCAN semilocal functional for self-interaction problems and noncovalent interactions. In particular, SCAN0-2, which includes about 79% of Hartree-Fock exchange and 50% of second-order Møller-Plesset correlation, is shown to be reliably accurate for a very diverse range of applications, such as thermochemistry, kinetics, noncovalent interactions, and self-interaction problems.

  13. A Neural Network-Based Gait Phase Classification Method Using Sensors Equipped on Lower Limb Exoskeleton Robots.

    PubMed

    Jung, Jun-Young; Heo, Wonho; Yang, Hyundae; Park, Hyunsub

    2015-10-30

    An exact classification of different gait phases is essential to enable the control of exoskeleton robots and detect the intentions of users. We propose a gait phase classification method based on neural networks using sensor signals from lower limb exoskeleton robots. In such robots, foot sensors with force sensing registers are commonly used to classify gait phases. We describe classifiers that use the orientation of each lower limb segment and the angular velocities of the joints to output the current gait phase. Experiments to obtain the input signals and desired outputs for the learning and validation process are conducted, and two neural network methods (a multilayer perceptron and nonlinear autoregressive with external inputs (NARX)) are used to develop an optimal classifier. Offline and online evaluations using four criteria are used to compare the performance of the classifiers. The proposed NARX-based method exhibits sufficiently good performance to replace foot sensors as a means of classifying gait phases.

  14. A Neural Network-Based Gait Phase Classification Method Using Sensors Equipped on Lower Limb Exoskeleton Robots

    PubMed Central

    Jung, Jun-Young; Heo, Wonho; Yang, Hyundae; Park, Hyunsub

    2015-01-01

    An exact classification of different gait phases is essential to enable the control of exoskeleton robots and detect the intentions of users. We propose a gait phase classification method based on neural networks using sensor signals from lower limb exoskeleton robots. In such robots, foot sensors with force sensing registers are commonly used to classify gait phases. We describe classifiers that use the orientation of each lower limb segment and the angular velocities of the joints to output the current gait phase. Experiments to obtain the input signals and desired outputs for the learning and validation process are conducted, and two neural network methods (a multilayer perceptron and nonlinear autoregressive with external inputs (NARX)) are used to develop an optimal classifier. Offline and online evaluations using four criteria are used to compare the performance of the classifiers. The proposed NARX-based method exhibits sufficiently good performance to replace foot sensors as a means of classifying gait phases. PMID:26528986

  15. Evidence-based guideline summary: Diagnosis and treatment of limb-girdle and distal dystrophies

    PubMed Central

    Narayanaswami, Pushpa; Weiss, Michael; Selcen, Duygu; David, William; Raynor, Elizabeth; Carter, Gregory; Wicklund, Matthew; Barohn, Richard J.; Ensrud, Erik; Griggs, Robert C.; Gronseth, Gary; Amato, Anthony A.

    2014-01-01

    Objective: To review the current evidence and make practice recommendations regarding the diagnosis and treatment of limb-girdle muscular dystrophies (LGMDs). Methods: Systematic review and practice recommendation development using the American Academy of Neurology guideline development process. Results: Most LGMDs are rare, with estimated prevalences ranging from 0.07 per 100,000 to 0.43 per 100,000. The frequency of some muscular dystrophies varies based on the ethnic background of the population studied. Some LGMD subtypes have distinguishing features, including pattern of muscle involvement, cardiac abnormalities, extramuscular involvement, and muscle biopsy findings. The few published therapeutic trials were not designed to establish clinical efficacy of any treatment. Principal recommendations: For patients with suspected muscular dystrophy, clinicians should use a clinical approach to guide genetic diagnosis based on clinical phenotype, inheritance pattern, and associated manifestations (Level B). Clinicians should refer newly diagnosed patients with an LGMD subtype and high risk of cardiac complications for cardiology evaluation even if they are asymptomatic from a cardiac standpoint (Level B). In patients with LGMD with a known high risk of respiratory failure, clinicians should obtain periodic pulmonary function testing (Level B). Clinicians should refer patients with muscular dystrophy to a clinic that has access to multiple specialties designed specifically to care for patients with neuromuscular disorders (Level B). Clinicians should not offer patients with LGMD gene therapy, myoblast transplantation, neutralizing antibody to myostatin, or growth hormone outside of a research study designed to determine efficacy and safety of the treatment (Level R). Detailed results and recommendations are available on the Neurology® Web site at Neurology.org. PMID:25313375

  16. Enhanced crosslimb transfer of force-field learning for dynamics that are identical in extrinsic and joint-based coordinates for both limbs.

    PubMed

    Carroll, Timothy J; de Rugy, Aymar; Howard, Ian S; Ingram, James N; Wolpert, Daniel M

    2016-01-01

    Humans are able to adapt their motor commands to make accurate movements in novel sensorimotor environments, such as when wielding tools that alter limb dynamics. However, it is unclear to what extent sensorimotor representations, obtained through experience with one limb, are available to the opposite, untrained limb and in which form they are available. Here, we compared crosslimb transfer of force-field compensation after participants adapted to a velocity-dependent curl field, oriented either in the sagittal or the transverse plane. Due to the mirror symmetry of the limbs, the force field had identical effects for both limbs in joint and extrinsic coordinates in the sagittal plane but conflicting joint-based effects in the transverse plane. The degree of force-field compensation exhibited by the opposite arm in probe trials immediately after initial learning was significantly greater after sagittal (26 ± 5%) than transverse plane adaptation (9 ± 4%; P < 0.001), irrespective of whether participants learned initially with the left or the right arm or via abrupt or gradual exposure to the force field. Thus transfer was impaired when the orientation of imposed dynamics conflicted in intrinsic coordinates for the two limbs. The data reveal that neural representations of novel dynamics are only partially available to the opposite limb, since transfer is incomplete even when force-field perturbation is spatially compatible for the two limbs, according to both intrinsic and extrinsic coordinates.

  17. Enhanced crosslimb transfer of force-field learning for dynamics that are identical in extrinsic and joint-based coordinates for both limbs

    PubMed Central

    de Rugy, Aymar; Howard, Ian S.; Ingram, James N.; Wolpert, Daniel M.

    2015-01-01

    Humans are able to adapt their motor commands to make accurate movements in novel sensorimotor environments, such as when wielding tools that alter limb dynamics. However, it is unclear to what extent sensorimotor representations, obtained through experience with one limb, are available to the opposite, untrained limb and in which form they are available. Here, we compared crosslimb transfer of force-field compensation after participants adapted to a velocity-dependent curl field, oriented either in the sagittal or the transverse plane. Due to the mirror symmetry of the limbs, the force field had identical effects for both limbs in joint and extrinsic coordinates in the sagittal plane but conflicting joint-based effects in the transverse plane. The degree of force-field compensation exhibited by the opposite arm in probe trials immediately after initial learning was significantly greater after sagittal (26 ± 5%) than transverse plane adaptation (9 ± 4%; P < 0.001), irrespective of whether participants learned initially with the left or the right arm or via abrupt or gradual exposure to the force field. Thus transfer was impaired when the orientation of imposed dynamics conflicted in intrinsic coordinates for the two limbs. The data reveal that neural representations of novel dynamics are only partially available to the opposite limb, since transfer is incomplete even when force-field perturbation is spatially compatible for the two limbs, according to both intrinsic and extrinsic coordinates. PMID:26581867

  18. A solar chromosphere and spicule model based on far-infrared limb observations

    NASA Technical Reports Server (NTRS)

    Braun, D.; Lindsey, C.

    1987-01-01

    Techniques developed for LTE radiative transfer problems in a rough atmosphere were used to compute a model chromosphere containing spicules consistent with high-resolution solar limb observations from 100 microns to 2.6 mm. The model consists of a smooth, plane-parallel temperature minimum region extending from the photosphere to a height of 1000 km and randomly distributed cylindrical spicules above this height. It is found that the observed limb brightness profiles are well fitted by spicules with electron temperatures on the order of 7000 K.

  19. Effect of flying altitude, scanning angle and scanning mode on the accuracy of ALS based forest inventory

    NASA Astrophysics Data System (ADS)

    Keränen, Juha; Maltamo, Matti; Packalen, Petteri

    2016-10-01

    Airborne laser scanning (ALS) is a widely used technology in the mapping of environment and forests. Data acquisition costs and the accuracy of the forest inventory are closely dependent on some extrinsic parameters of the ALS survey. These parameters have been assessed in numerous studies about a decade ago, but since then ALS devices have developed and it is possible that previous findings do not hold true with newer technology. That is why, the effect of flying altitudes (2000, 2500 or 3000 m), scanning angles (±15° and ±20° off nadir) and scanning modes (single- and multiple pulses in air) with the area-based approach using a Leica ALS70HA-laser scanner was studied here. The study was conducted in a managed pine-dominated forest area in Finland, where eight separate discrete-return ALS data were acquired. The comparison of datasets was based on the bootstrap approach with 5-fold cross validation. Results indicated that the narrower scanning angle (±15° i.e. 30°) led to slightly more accurate estimates of plot volume (RMSE%: 21-24 vs. 22.5-25) and mean height (RMSE%: 8.5-11 vs. 9-12). We also tested the use case where the models are constructed using one data and then applied to other data gathered with different parameters. The most accurate models were identified using the bootstrap approach and applied to different datasets with and without refitting. The bias increased without refitting the models (bias%: volume 0 ± 10, mean height 0 ± 3), but in most cases the results did not differ much in terms of RMSE%. This confirms previous observations that models should only be used for datasets collected under similar data acquisition conditions. We also calculated the proportions of echoes as a function of height for different echo categories. This indicated that the accuracy of the inventory is affected more by the height distribution than the proportions of echo categories.

  20. Microvascular quantification based on contour-scanning photoacoustic microscopy

    PubMed Central

    Yeh, Chenghung; Soetikno, Brian; Hu, Song; Maslov, Konstantin I.; Wang, Lihong V.

    2014-01-01

    Abstract. Accurate quantification of microvasculature remains of interest in fundamental pathophysiological studies and clinical trials. Current photoacoustic microscopy can noninvasively quantify properties of the microvasculature, including vessel density and diameter, with a high spatial resolution. However, the depth range of focus (i.e., focal zone) of optical-resolution photoacoustic microscopy (OR-PAM) is often insufficient to encompass the depth variations of features of interest—such as blood vessels—due to uneven tissue surfaces. Thus, time-consuming image acquisitions at multiple different focal planes are required to maintain the region of interest in the focal zone. We have developed continuous three-dimensional motorized contour-scanning OR-PAM, which enables real-time adjustment of the focal plane to track the vessels’ profile. We have experimentally demonstrated that contour scanning improves the signal-to-noise ratio of conventional OR-PAM by as much as 41% and shortens the image acquisition time by 3.2 times. Moreover, contour-scanning OR-PAM more accurately quantifies vessel density and diameter, and has been applied to studying tumors with uneven surfaces. PMID:25223708

  1. Pediatric limb differences and amputations.

    PubMed

    Le, Joan T; Scott-Wyard, Phoebe R

    2015-02-01

    Congenital limb differences are uncommon birth defects that may go undetected even with prenatal screening ultrasound scans and often go undetected until birth. For children with congenital limb differences, a diagnostic evaluation should be done to rule out syndromes involving other organ systems or known associations. The most common etiology of acquired amputation is trauma. Postamputation complications include pain and terminal bony overgrowth. A multidisciplinary approach to management with the child and family can lead to a successful, functional, and fulfilling life.

  2. Control of a pneumatic power active lower-limb orthosis with filter-based iterative learning control

    NASA Astrophysics Data System (ADS)

    Huang, Chia-En; Chen, Jian-Shiang

    2014-05-01

    A filter-based iterative learning control (FILC) scheme is developed in this paper, which consists in a proportional-derivative (PD) feedback controller and a feedforward filter. Moreover, based on two-dimensional system theory, the stability of the FILC system is proven. The design criteria for a wavelet transform filter (WTF) - chosen as the feedforward filter - and the PD feedback controller are also given. Finally, using a pneumatic power active lower-limb orthosis (PPALO) as the controlled plant, the wavelet-based iterative learning control (WILC) implementation and the orchestration of a trajectory tracking control simulation are given in detail and the overall tracking performance is validated.

  3. Comparison of point target detection algorithms for space-based scanning infrared sensors

    NASA Astrophysics Data System (ADS)

    Namoos, Omar M.; Schulenburg, Nielson W.

    1995-09-01

    The tracking of resident space objects (RSO) by space-based sensors can lead to engagements that result in stressing backgrounds. These backgrounds, including hard earth, earth limb, and zodiacal, pose various difficulties for signal processing algorithms designed to detect and track the target with a minimum of false alarms. Simulated RSO engagements were generated using the Strategic Scene Generator Model and a sensor model to create focal plane scenes. Using this data, the performance of several detection algorithms has been quantified for space, earth limb and cluttered hard earth backgrounds. These algorithms consist of an adaptive spatial filter, a transversal (matched) filters, and a median variance (nonlinear) filter. Signal-to-clutter statistics of the filtered scenes are compared to those of the unfiltered scene. False alarm and detection results are included. Based on these findings, a suggested processing software architectures design is hypothesized.

  4. Development of exoskeletal robotic limbs for a rat controlled by neural signals based on a vehicular neuro-robotic platform RatCar.

    PubMed

    Fukayama, Osamu; Otsuka, Hiroshi; Hashimoto, Ryuta; Suzuki, Takafumi; Mabuchi, Kunihiko

    2012-01-01

    A pair of exoskeletal limbs for a rat has been developed based on a vehicular Brain-Machine Interface "Rat-Car". The "RatCar" is a whole-body motor prosthesis system for a rat developed by the authors, estimating locomotion velocity according to neural signals pattern to move the rat body by the vehicle instead of its original limbs. In this paper, exoskeletal limbs have displaced the wheels for more natural modality of body control. The system was tested by applying peripheral nerve signals from a behaving rat.

  5. A scanning acoustic microscope based on picosecond ultrasonics.

    PubMed

    Che, S; Guduru, P R; Nurmikko, A V; Maris, H J

    2015-02-01

    We report on the development of a new type of scanning acoustic microscope. We use a femtosecond light pulse to generate a short sound pulse, and then focus this sound onto the sample by means of a specially designed and microfabricated acoustic lens of radius a few microns. The sound travels to the sample through a thin layer of water. The sound reflected from the sample is collected by the lens and then passes through a monolithically integrated optical resonant cavity. The induced change in the properties of this cavity are measured using a time-delayed probe light pulse. We describe some of the challenges involved in the construction and operation of this high-precision metrology apparatus and present some preliminary results.

  6. Transducer and base compliance alter the in situ 6 dof force measured from muscle during an isometric contraction in a multi-joint limb.

    PubMed

    Sandercock, Thomas G; Yeo, Sang Hoon; Pai, Dinesh K; Tresch, Matthew C

    2012-04-05

    Although musculoskeletal models are commonly used, validating the muscle actions predicted by such models is often difficult. In situ isometric measurements are a possible solution. The base of the skeleton is immobilized and the endpoint of the limb is rigidly attached to a 6-axis force transducer. Individual muscles are stimulated and the resulting forces and moments recorded. Such analyses generally assume idealized conditions. In this study we have developed an analysis taking into account the compliances due to imperfect fixation of the skeleton, imperfect attachment of the force transducer, and extra degrees of freedom (dof) in the joints that sometimes become necessary in fixed end contractions. We use simulations of the rat hindlimb to illustrate the consequences of such compliances. We show that when the limb is overconstrained, i.e., when there are fewer dof within the limb than are restrained by the skeletal fixation, the compliances of the skeletal fixation and of the transducer attachment can significantly affect measured forces and moments. When the limb dofs and restrained dofs are matched, however, the measured forces and moments are independent of these compliances. We also show that this framework can be used to model limb dofs, so that rather than simply omitting dofs in which a limb does not move (e.g., abduction at the knee), the limited motion of the limb in these dofs can be more realistically modeled as a very low compliance. Finally, we discuss the practical implications of these results to experimental measurements of muscle actions.

  7. Action observation for upper limb function after stroke: evidence-based review of randomized controlled trials

    PubMed Central

    Kim, KyeongMi

    2015-01-01

    [Purpose] The purpose of this study was to suggest evidenced information about action observation to improve upper limb function after stroke. [Methods] A systematic review of randomized controlled trials involving adults aged 18 years or over and including descriptions of action observation for improving upper limb function was undertaken. Electronic databases were searched, including MEDLINE, CINAHL, and PEDro (the Physiotherapy Evidence Database), for articles published between 2000 to 2014. Following completion of the searches, two reviewers independently assessed the trials and extracted data using a data extraction form. The same two reviewers independently documented the methodological quality of the trials by using the PEDro scale. [Results] Five randomized controlled trials were ultimately included in this review, and four of them (80%) reported statistically significant effects for motor recovery of upper limb using action observation intervention in between groups. [Conclusion] This review of the literature presents evidence attesting to the benefits conferred on stroke patints resulting from participation in an action observation intervention. The body of literature in this field is growing steadily. Further work needs to be done to evaluate the evidence for different conditions after stroke and different duration of intervention. PMID:26644700

  8. Measure and Control Technology Based on DSP for HighPrecision Scanning Motor

    NASA Astrophysics Data System (ADS)

    Yang, N.; Yang, X. Y.; Wu, B.; Ye, S. H.

    2006-10-01

    A welding seam tracking visual sensor based on laser scanning is designed to solve the problems, such as indistinct image, difficulty in processing image etc., caused by serious arc light interference during welding. This visual sensor is mainly composed of a scanning motor, a linear-array CCD, a scanning rotating mirror and a semiconductor laser. Because the sensor measurement precision relies dramatically on the rotate speed stability of the scanning motor, the crux in the sensor design is to control the rotate speed of the scanning motor. Selecting a brushless direct current motor as the scanning motor and using TMS320F2812 DSP to drive it, we adopted fuzzy algorithm to control the motor rotate speed and made the steadiness error of the rotate speed less than 0.5%, which guarantees the sensor measurement precision and is of great importance for enhancing the welding quality of the industry welding robot.

  9. A line segment based registration method for Terrestrial Laser Scanning point cloud data

    NASA Astrophysics Data System (ADS)

    Cheng, Jun; Cheng, Ming; Lin, Yangbin; Wang, Cheng

    2016-03-01

    This paper proposed a 3d line segment based registration method for terrestrial laser scanning (TLS) data. The 3D line segment is adopted to describe the point cloud data and reduce geometric complexity. After that, we introduce a framework for registration. We demonstrate the accuracy of our method for rigid transformations in the presence of terrestrial laser scanning point cloud.

  10. Scanning laser beam displays based on a 2D MEMS

    NASA Astrophysics Data System (ADS)

    Niesten, Maarten; Masood, Taha; Miller, Josh; Tauscher, Jason

    2010-05-01

    The combination of laser light sources and MEMS technology enables a range of display systems such as ultra small projectors for mobile devices, head-up displays for vehicles, wearable near-eye displays and projection systems for 3D imaging. Images are created by scanning red, green and blue lasers horizontally and vertically with a single two-dimensional MEMS. Due to the excellent beam quality of laser beams, the optical designs are efficient and compact. In addition, the laser illumination enables saturated display colors that are desirable for augmented reality applications where a virtual image is used. With this technology, the smallest projector engine for high volume manufacturing to date has been developed. This projector module has a height of 7 mm and a volume of 5 cc. The resolution of this projector is WVGA. No additional projection optics is required, resulting in an infinite focus depth. Unlike with micro-display projection displays, an increase in resolution will not lead to an increase in size or a decrease in efficiency. Therefore future projectors can be developed that combine a higher resolution in an even smaller and thinner form factor with increased efficiencies that will lead to lower power consumption.

  11. Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron microscopy.

    PubMed

    You, Yun-Wen; Chang, Hsun-Yun; Liao, Hua-Yang; Kao, Wei-Lun; Yen, Guo-Ji; Chang, Chi-Jen; Tsai, Meng-Hung; Shyue, Jing-Jong

    2012-10-01

    Based on a scanning electron microscope operated at 30 kV with a homemade specimen holder and a multiangle solid-state detector behind the sample, low-kV scanning transmission electron microscopy (STEM) is presented with subsequent electron tomography for three-dimensional (3D) volume structure. Because of the low acceleration voltage, the stronger electron-atom scattering leads to a stronger contrast in the resulting image than standard TEM, especially for light elements. Furthermore, the low-kV STEM yields less radiation damage to the specimen, hence the structure can be preserved. In this work, two-dimensional STEM images of a 1-μm-thick cell section with projection angles between ±50° were collected, and the 3D volume structure was reconstructed using the simultaneous iterative reconstructive technique algorithm with the TomoJ plugin for ImageJ, which are both public domain software. Furthermore, the cross-sectional structure was obtained with the Volume Viewer plugin in ImageJ. Although the tilting angle is constrained and limits the resulting structural resolution, slicing the reconstructed volume generated the depth profile of the thick specimen with sufficient resolution to examine cellular uptake of Au nanoparticles, and the final position of these nanoparticles inside the cell was imaged.

  12. The development of a segment-based musculoskeletal model of the lower limb: introducing FreeBody

    PubMed Central

    Cleather, Daniel J.; Bull, Anthony M. J.

    2015-01-01

    Traditional approaches to the biomechanical analysis of movement are joint-based; that is the mechanics of the body are described in terms of the forces and moments acting at the joints, and that muscular forces are considered to create moments about the joints. We have recently shown that segment-based approaches, where the mechanics of the body are described by considering the effect of the muscle, ligament and joint contact forces on the segments themselves, can also prove insightful. We have also previously described a simultaneous, optimization-based, musculoskeletal model of the lower limb. However, this prior model incorporates both joint- and segment-based assumptions. The purpose of this study was therefore to develop an entirely segment-based model of the lower limb and to compare its performance to our previous work. The segment-based model was used to estimate the muscle forces found during vertical jumping, which were in turn compared with the muscular activations that have been found in vertical jumping, by using a Geers' metric to quantify the magnitude and phase errors. The segment-based model was shown to have a similar ability to estimate muscle forces as a model based upon our previous work. In the future, we will evaluate the ability of the segment-based model to be used to provide results with clinical relevance, and compare its performance to joint-based approaches. The segment-based model described in this article is publicly available as a GUI-based Matlab® application and in the original source code (at www.msksoftware.org.uk). PMID:26543569

  13. Stiffness-based tuning of an adaptive impedance controller for robot-assisted rehabilitation of upper limbs.

    PubMed

    Maldonado, Berenice; Mendoza, Marco; Bonilla, Isela; Reyna-Gutiérrez, Iván

    2015-08-01

    In this paper, the tuning procedure of an adaptive impedance control approach, for upper limb rehabilitation therapies assisted by robots, is presented. The main feature of the proposed approach is a custom tuning of the impedance parameters for the controller, based on the stiffness estimation of users (patients), thus achieving a suitable robot-assisted rehabilitation system according with the different conditions of user's mobility. A set of simulation results are presented, in order to verify the suitable performance of the proposed approach in human-robot interaction tasks.

  14. Point-based and model-based geolocation analysis of airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Sefercik, Umut Gunes; Buyuksalih, Gurcan; Jacobsen, Karsten; Alkan, Mehmet

    2017-01-01

    Airborne laser scanning (ALS) is one of the most effective remote sensing technologies providing precise three-dimensional (3-D) dense point clouds. A large-size ALS digital surface model (DSM) covering the whole Istanbul province was analyzed by point-based and model-based comprehensive statistical approaches. Point-based analysis was performed using checkpoints on flat areas. Model-based approaches were implemented in two steps as strip to strip comparing overlapping ALS DSMs individually in three subareas and comparing the merged ALS DSMs with terrestrial laser scanning (TLS) DSMs in four other subareas. In the model-based approach, the standard deviation of height and normalized median absolute deviation were used as the accuracy indicators combined with the dependency of terrain inclination. The results demonstrate that terrain roughness has a strong impact on the vertical accuracy of ALS DSMs. From the relative horizontal shifts determined and partially improved by merging the overlapping strips and comparison of the ALS, and the TLS, data were found not to be negligible. The analysis of ALS DSM in relation to TLS DSM allowed us to determine the characteristics of the DSM in detail.

  15. Acousto-optical deflection-based laser beam scanning for fluorescence detection on multichannel electrophoretic microchips.

    PubMed

    Huang, Z; Munro, N; Hühmer, A F; Landers, J P

    1999-12-01

    Laser beam scanning driven by an acousto-optical deflector (AOD) is presented for multimicrochannel laser-induced fluorescence (LIF) detection during microchip-based electrophoresis. While fast laser beam scanning for LIF detection on capillary or microchannel arrays can been achieved with galvanometric scanning or a translating stage, it can also be accomplished by using acoustic waves to deflect the laser beam in a manner that is dependent on the acoustic frequency. AOD scanning differs from other approaches in that no moving parts are required, and the scan frequency is faster than conventional approaches. Using a digital/analog (D/A) converter to provide addressing voltages to a voltage/frequency converter, rapidly changing the frequency input to the AOD allows the laser beam to be addressed accurately on a microchip. With the ability to change the frequency on the nanosecond time scale, scanning rates as high as 30 Hz for Windows-based LabView programming are possible, with much faster scan rates achievable if a microprocessor-embedded system is utilized. In addition to spatial control, temporal control is easily attainable via raster scanning or random addressing, allowing for the scanning process to be self-aligning. Since the D/A output voltages drive the scanning of the laser beam over all channels, the software can define addressing voltages corresponding to the microchannel centers and, subsequently, fluorescence data can be collected from only those locations. This method allows for flexible, high-speed, self-align scanning for fluorescence detection in capillary or microchip electrophoresis and has the potential to be applied to a number of applications.

  16. Recognition Method of Limb Motor Imagery EEG Signals Based on Integrated Back-propagation Neural Network.

    PubMed

    Li, Mingyang; Chen, Wanzhong; Cui, Bingyi; Tian, Yantao

    2015-01-01

    In this paper, in order to solve the existing problems of the low recognition rate and poor real-time performance in limb motor imagery, the integrated back-propagation neural network (IBPNN) was applied to the pattern recognition research of motor imagery EEG signals (imagining left-hand movement, imagining right-hand movement and imagining no movement). According to the motor imagery EEG data categories to be recognized, the IBPNN was designed to consist of 3 single three-layer back-propagation neural networks (BPNN), and every single neural network was dedicated to recognizing one kind of motor imagery. It simplified the complicated classification problems into three mutually independent two-class classifications by the IBPNN. The parallel computing characteristic of IBPNN not only improved the generation ability for network, but also shortened the operation time. The experimental results showed that, while comparing the single BPNN and Elman neural network, IBPNN was more competent in recognizing limb motor imagery EEG signals. Also among these three networks, IBPNN had the least number of iterations, the shortest operation time and the best consistency of actual output and expected output, and had lifted the success recognition rate above 97 percent while other single network is around 93 percent.

  17. A Serious Game for Upper Limb Stroke Rehabilitation Using Biofeedback and Mirror-Neurons Based Training.

    PubMed

    Cargnin, Diego João; Cordeiro d'Ornellas, Marcos; Cervi Prado, Ana Lúcia

    2015-01-01

    Upper limb stroke rehabilitation requires early, intensive and repetitive practice to be effective. Consequently, it is often difficult to keep patients committed to their rehabilitation regimen. In addition to direct measures of rehabilitation achievable through targeted assessments, other factors can indirectly lead to rehabilitation. Current levels of integration between commodity graphics software, hardware, and body-tracking devices have provided a reliable tool to build what are referred to as serious games, focusing on the rehabilitation paradigm. More specifically, serious games can captivate and engage players for a specific purpose such as developing new knowledge or skills. This paper discusses a serious game application with a focus on upper limb rehabilitation in patients with hemiplegia or hemiparesis. The game makes use of biofeedback and mirror-neurons to enhance the patient's engagement. Results from the application of a quantitative self-report instrument to assess in-game engagement suggest that the serious game is a viable instructional approach rather than an entertaining novelty and, furthermore, demonstrates the future potential for dual action therapy-focused games.

  18. Pretreatment with Fish Oil-Based Lipid Emulsion Modulates Muscle Leukocyte Chemotaxis in Murine Model of Sublethal Lower Limb Ischemia

    PubMed Central

    Shih, Yao-Ming; Shih, Juey-Ming; Yeh, Chiu-Li; Li, Cheng-Che

    2017-01-01

    This study investigated the effects of a fish oil- (FO-) based lipid emulsion on muscle leukocyte chemotaxis and inflammatory responses in a murine model of limb ischemia-reperfusion (IR) injury. Mice were assigned randomly to 1 sham (sham) group, 2 ischemic groups, and 2 IR groups. The sham group did not undergo the ischemic procedure. The mice assigned to the ischemic or IR groups were pretreated intraperitoneally with either saline or FO-based lipid emulsion for 3 consecutive days. The IR procedure was induced by applying a 4.5 oz orthodontic rubber band to the left thigh above the greater trochanter for 120 min and then cutting the band to allow reperfusion. The ischemic groups were sacrificed immediately while the IR groups were sacrificed 24 h after reperfusion. Blood, IR-injured gastrocnemius, and lung tissues were collected for analysis. The results showed that FO pretreatment suppressed the local and systemic expression of several IR-induced proinflammatory mediators. Also, the FO-pretreated group had lower blood Ly6ChiCCR2hi monocyte percentage and muscle M1/M2 ratio than the saline group at 24 h after reperfusion. These findings suggest that FO pretreatment may have a protective role in limb IR injury by modulating the expression of proinflammatory mediators and regulating the polarization of macrophage. PMID:28182087

  19. Automatic indexing of scanned documents: a layout-based approach

    NASA Astrophysics Data System (ADS)

    Esser, Daniel; Schuster, Daniel; Muthmann, Klemens; Berger, Michael; Schill, Alexander

    2012-01-01

    Archiving official written documents such as invoices, reminders and account statements in business and private area gets more and more important. Creating appropriate index entries for document archives like sender's name, creation date or document number is a tedious manual work. We present a novel approach to handle automatic indexing of documents based on generic positional extraction of index terms. For this purpose we apply the knowledge of document templates stored in a common full text search index to find index positions that were successfully extracted in the past.

  20. Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT.

    PubMed

    Duma, Virgil-Florin; Lee, Kye-sung; Meemon, Panomsak; Rolland, Jannick P

    2011-10-10

    We analyze the three most common profiles of scanning functions for galvanometer-based scanners (GSs): the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e., frequency and amplitude). We study the differences of the output function of the GS measured as the positional error of the oscillatory mirror from the ideal function given by the input signal of the device. The limits in achieving the different types of scanning functions in terms of duty cycle and linearity are determined experimentally for the possible range of scan parameters. Of particular importance are the preservation of an imposed duty cycle and profile for the sawtooth function, the quantification of the linearity for the sinusoidal function, and the effective duty cycle for the triangular, as well as for the other functions. The range of scan amplitudes for which the stability of the oscillatory regime of the galvo mirror is stable for different frequencies is also highlighted. While the use of the device in certain scanning regimes is studied, certain rules of thumb are deduced to make the best out of the galvoscanner. Finally, the three types of scanning functions are tested with a Fourier domain optical coherence tomography (FD OCT) setup and the conclusions of the study are demonstrated in an imaging application by correlating the determined limits of the scanning regimes with the requirements of OCT.

  1. PE-CMOS based C-scan ultrasound for foreign object detection in soft tissue.

    PubMed

    Liu, Chu-Chuan; Lo, Shih-Chung Ben; Freedman, Matthew T; Lasser, Marvin E; Kula, John; Sarcone, Anita; Wang, Yue

    2010-01-01

    In this paper, we introduce a C-scan ultrasound prototype and three imaging modalities for the detection of foreign objects inserted in porcine soft tissue. The object materials include bamboo, plastics, glass and aluminum alloys. The images of foreign objects were acquired using the C-scan ultrasound, a portable B-scan ultrasound, film-based radiography, and computerized radiography. The C-scan ultrasound consists of a plane wave transducer, a compound acoustic lens system, and a newly developed ultrasound sensor array based on the complementary metal-oxide semiconductor coated with piezoelectric material (PE-CMOS). The contrast-to-noise ratio (CNR) of the images were analyzed to quantitatively evaluate the detectability using different imaging modalities. The experimental results indicate that the C-scan prototype has better CNR values in 4 out of 7 objects than other modalities. Specifically, the C-scan prototype provides more detail information of the soft tissues without the speckle artifacts that are commonly seen with conventional B-scan ultrasound, and has the same orientation as the standard radiographs but without ionizing radiation.

  2. Two-axis polydimethylsiloxane-based electromagnetic microelectromechanical system scanning mirror for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Kim, Sehui; Lee, Changho; Kim, Jin Young; Kim, Jeehyun; Lim, Geunbae; Kim, Chulhong

    2016-10-01

    Compact size and fast imaging abilities are key requirements for the clinical implementation of an optical coherence tomography (OCT) system. Among the various small-sized technology, a microelectromechanical system (MEMS) scanning mirror is widely used in a miniaturized OCT system. However, the complexities of conventional MEMS fabrication processes and relatively high costs have restricted fast clinical translation and commercialization of the OCT systems. To resolve these problems, we developed a two-axis polydimethylsiloxane (PDMS)-based MEMS (2A-PDMS-MEMS) scanning mirror through simple processes with low costs. It had a small size of 15×15×15 mm3, was fast, and had a wide scanning range at a low voltage. The AC/DC responses were measured to evaluate the performance of the 2A-PDMS-MEMS scanning mirror. The maximum scanning angles were measured as ±16.6 deg and ±11.6 deg along the X and Y axes, respectively, and the corresponding field of view was 29.8 mm×20.5 mm with an optical focal length of 50 mm. The resonance frequencies were 82 and 57 Hz along the X and Y axes, respectively. Finally, in vivo B-scan and volumetric OCT images of human fingertips and palms were successfully acquired using the developed SD-OCT system based on the 2A-PDMS-MEMS scanning mirror.

  3. RNAi-based Gene Therapy for Dominant Limb Girdle Muscular Dystrophies

    PubMed Central

    Liu, Jian; Harper, Scott Q.

    2014-01-01

    Limb Girdle Muscular Dystrophy (LGMD) refers to a group of 25 genetic diseases linked by common clinical features, including wasting of muscles supporting the pelvic and shoulder girdles. Cardiac involvement may also occur. Like other muscular dystrophies, LGMDs are currently incurable, but prospective gene replacement therapies targeting recessive forms have shown promise in pre-clinical and clinical studies. In contrast, little attention has been paid to developing gene therapy approaches for dominant forms of LGMD, which would likely benefit from disease gene silencing. Despite the lack of focus to date on developing gene therapies for dominant LGMDs, the field is not starting at square one, since translational studies on recessive LGMDs provided a framework that can be applied to treating dominant forms of the disease. In this manuscript, we discuss the prospects of treating dominantly inherited forms of LGMD with gene silencing approaches. PMID:22856606

  4. Grebe dysplasia - prenatal diagnosis based on rendered 3-D ultrasound images of fetal limbs.

    PubMed

    Goncalves, Luis F; Berger, Julie A; Macknis, Jacqueline K; Bauer, Samuel T; Bloom, David A

    2017-01-01

    Grebe dysplasia is a rare skeletal dysplasia characterized by severe acromesomelic shortening of the long bones in a proximal to distal gradient of severity, with bones of the hands and feet more severely affected than those of the forearms and legs, which in turn are more severely affected than the humeri and femora. In addition, the bones of the lower extremities tend to be more severely affected than the bones of the upper extremities. Despite the severe skeletal deformities, the condition is not lethal and surviving individuals can have normal intelligence. Herein we report a case of Grebe dysplasia diagnosed at 20 weeks of gestation. Rendered 3-D ultrasound images of the fetal limbs, particularly of the characteristic tiny and globular-looking fingers and toes, were instrumental in accurately characterizing the phenotype prenatally.

  5. Performance of new GPU-based scan-conversion algorithm implemented using OpenGL.

    PubMed

    Steelman, William A; Richard, William D

    2011-04-01

    A new GPU-based scan-conversion algorithm implemented using OpenGL is described. The compute performance of this new algorithm running on a modem GPU is compared to the performance of three common scan-conversion algorithms (nearest-neighbor, linear interpolation and bilinear interpolation) implemented in software using a modem CPU. The quality of the images produced by the algorithm, as measured by signal-to-noise power, is also compared to the quality of the images produced using these three common scan-conversion algorithms.

  6. High-fidelity AFM scanning stage based on multilayer ceramic capacitors.

    PubMed

    Chen, Jian; Zhang, Lian Sheng; Feng, Zhi Hua

    2016-05-01

    A kind of multilayer ceramic capacitors (MLCCs) has been verified to have good micro-actuating properties, thus making them good candidates for nano-positioning. In this paper, we successfully employed the MLCCs as lateral scanners for a tripod scanning stage. The MLCC-based lateral scanners display hysteresis under 1.5% and a nonlinearity less than 2% even with the simplest open-loop voltage drive. The developed scanning stage was integrated into a commercial AFM to evaluate its imaging performance. Experimental results showed that sample images with high fidelities were obtained. SCANNING 38:184-190, 2016. © 2015 Wiley Periodicals, Inc.

  7. A Brain-Machine Interface Based on ERD/ERS for an Upper-Limb Exoskeleton Control.

    PubMed

    Tang, Zhichuan; Sun, Shouqian; Zhang, Sanyuan; Chen, Yumiao; Li, Chao; Chen, Shi

    2016-12-02

    To recognize the user's motion intention, brain-machine interfaces (BMI) usually decode movements from cortical activity to control exoskeletons and neuroprostheses for daily activities. The aim of this paper is to investigate whether self-induced variations of the electroencephalogram (EEG) can be useful as control signals for an upper-limb exoskeleton developed by us. A BMI based on event-related desynchronization/synchronization (ERD/ERS) is proposed. In the decoder-training phase, we investigate the offline classification performance of left versus right hand and left hand versus both feet by using motor execution (ME) or motor imagery (MI). The results indicate that the accuracies of ME sessions are higher than those of MI sessions, and left hand versus both feet paradigm achieves a better classification performance, which would be used in the online-control phase. In the online-control phase, the trained decoder is tested in two scenarios (wearing or without wearing the exoskeleton). The MI and ME sessions wearing the exoskeleton achieve mean classification accuracy of 84.29% ± 2.11% and 87.37% ± 3.06%, respectively. The present study demonstrates that the proposed BMI is effective to control the upper-limb exoskeleton, and provides a practical method by non-invasive EEG signal associated with human natural behavior for clinical applications.

  8. A Brain-Machine Interface Based on ERD/ERS for an Upper-Limb Exoskeleton Control

    PubMed Central

    Tang, Zhichuan; Sun, Shouqian; Zhang, Sanyuan; Chen, Yumiao; Li, Chao; Chen, Shi

    2016-01-01

    To recognize the user’s motion intention, brain-machine interfaces (BMI) usually decode movements from cortical activity to control exoskeletons and neuroprostheses for daily activities. The aim of this paper is to investigate whether self-induced variations of the electroencephalogram (EEG) can be useful as control signals for an upper-limb exoskeleton developed by us. A BMI based on event-related desynchronization/synchronization (ERD/ERS) is proposed. In the decoder-training phase, we investigate the offline classification performance of left versus right hand and left hand versus both feet by using motor execution (ME) or motor imagery (MI). The results indicate that the accuracies of ME sessions are higher than those of MI sessions, and left hand versus both feet paradigm achieves a better classification performance, which would be used in the online-control phase. In the online-control phase, the trained decoder is tested in two scenarios (wearing or without wearing the exoskeleton). The MI and ME sessions wearing the exoskeleton achieve mean classification accuracy of 84.29% ± 2.11% and 87.37% ± 3.06%, respectively. The present study demonstrates that the proposed BMI is effective to control the upper-limb exoskeleton, and provides a practical method by non-invasive EEG signal associated with human natural behavior for clinical applications. PMID:27918413

  9. Assessing the impact of upper limb disability following stroke: a qualitative enquiry using internet-based personal accounts of stroke survivors

    PubMed Central

    Poltawski, Leon; Allison, Rhoda; Briscoe, Simon; Freeman, Jennifer; Kilbride, Cherry; Neal, Debbie; Turton, Ailie J.; Dean, Sarah

    2016-01-01

    Abstract Purpose: Upper limb disability following stroke may have multiple effects on the individual. Existing assessment instruments tend to focus on impairment and function and may miss other changes that are personally important. This study aimed to identify personally significant impacts of upper limb disability following stroke. Methods: Accounts by stroke survivors, in the form of web-based diaries (blogs) and stories, were sought using a blog search engine and in stroke-related web-sites. Thematic analysis using the World Health Organisation’s International Classification of Functioning Disability and Health (ICF) was used to identify personal impacts of upper limb disability following stroke. Results: Ninety-nine sources from at least four countries were analysed. Many impacts were classifiable using the ICF, but a number of additional themes emerged, including emotional, cognitive and behavioural changes. Blogs and other web-based accounts were easily accessible and rich sources of data, although using them raised several methodological issues, including potential sample bias. Conclusions: A range of impacts was identified, some of which (such as use of information technology and alienation from the upper limb) are not addressed in current assessment instruments. They should be considered in post-stroke assessments. Blogs may help in the development of more comprehensive assessments.Implications for RehabilitationA comprehensive assessment of the upper limb following stroke should include the impact of upper limb problems on social participation, as well as associated emotional, cognitive and behavioural changes.Using personalised assessment instruments alongside standardised measures may help ensure that these broader domains are considered in discussions between clinicians and patients.Rehabilitation researchers should investigate whether and how these domains could be addressed and operationalised in standard upper limb assessment instruments. PMID

  10. Lower limb examinations for muscular tension estimation methods for each muscle group based on functionally different effective muscle theory.

    PubMed

    Nishii, Taiki; Komada, Satoshi; Yashiro, Daisuke; Hirai, Junji

    2013-01-01

    Conventional estimation methods distribute tension to muscles by solving optimization problems, because the system is redundant. The theory of functionally different effective muscle, based on 3 antagonistic pairs of muscle groups in limbs, has enabled to calculate the maximum joint torque of each pair, i.e. functionally different effective muscle force. Based on this theory, a method to estimate muscular tension has been proposed, where joint torque of each muscle group is derived by multiplying functionally different effective muscle force, the muscular activity of muscular activity pattern for direction of tip force, and ratio of tip force to maximum output force. The estimation of this method is as good as Crowninshield's method, moreover this method also reduce the computation time if the estimation concerns a selected muscle group.

  11. Optical scanning holography based on compressive sensing using a digital micro-mirror device

    NASA Astrophysics Data System (ADS)

    A-qian, Sun; Ding-fu, Zhou; Sheng, Yuan; You-jun, Hu; Peng, Zhang; Jian-ming, Yue; xin, Zhou

    2017-02-01

    Optical scanning holography (OSH) is a distinct digital holography technique, which uses a single two-dimensional (2D) scanning process to record the hologram of a three-dimensional (3D) object. Usually, these 2D scanning processes are in the form of mechanical scanning, and the quality of recorded hologram may be affected due to the limitation of mechanical scanning accuracy and unavoidable vibration of stepper motor's start-stop. In this paper, we propose a new framework, which replaces the 2D mechanical scanning mirrors with a Digital Micro-mirror Device (DMD) to modulate the scanning light field, and we call it OSH based on Compressive Sensing (CS) using a digital micro-mirror device (CS-OSH). CS-OSH can reconstruct the hologram of an object through the use of compressive sensing theory, and then restore the image of object itself. Numerical simulation results confirm this new type OSH can get a reconstructed image with favorable visual quality even under the condition of a low sample rate.

  12. Exploring the bases for a mixed reality stroke rehabilitation system, Part II: Design of Interactive Feedback for upper limb rehabilitation

    PubMed Central

    2011-01-01

    Background Few existing interactive rehabilitation systems can effectively communicate multiple aspects of movement performance simultaneously, in a manner that appropriately adapts across various training scenarios. In order to address the need for such systems within stroke rehabilitation training, a unified approach for designing interactive systems for upper limb rehabilitation of stroke survivors has been developed and applied for the implementation of an Adaptive Mixed Reality Rehabilitation (AMRR) System. Results The AMRR system provides computational evaluation and multimedia feedback for the upper limb rehabilitation of stroke survivors. A participant's movements are tracked by motion capture technology and evaluated by computational means. The resulting data are used to generate interactive media-based feedback that communicates to the participant detailed, intuitive evaluations of his performance. This article describes how the AMRR system's interactive feedback is designed to address specific movement challenges faced by stroke survivors. Multimedia examples are provided to illustrate each feedback component. Supportive data are provided for three participants of varying impairment levels to demonstrate the system's ability to train both targeted and integrated aspects of movement. Conclusions The AMRR system supports training of multiple movement aspects together or in isolation, within adaptable sequences, through cohesive feedback that is based on formalized compositional design principles. From preliminary analysis of the data, we infer that the system's ability to train multiple foci together or in isolation in adaptable sequences, utilizing appropriately designed feedback, can lead to functional improvement. The evaluation and feedback frameworks established within the AMRR system will be applied to the development of a novel home-based system to provide an engaging yet low-cost extension of training for longer periods of time. PMID:21899779

  13. Robust Sliding Mode Control Based on GA Optimization and CMAC Compensation for Lower Limb Exoskeleton

    PubMed Central

    Long, Yi; Du, Zhi-jiang; Wang, Wei-dong; Dong, Wei

    2016-01-01

    A lower limb assistive exoskeleton is designed to help operators walk or carry payloads. The exoskeleton is required to shadow human motion intent accurately and compliantly to prevent incoordination. If the user's intention is estimated accurately, a precise position control strategy will improve collaboration between the user and the exoskeleton. In this paper, a hybrid position control scheme, combining sliding mode control (SMC) with a cerebellar model articulation controller (CMAC) neural network, is proposed to control the exoskeleton to react appropriately to human motion intent. A genetic algorithm (GA) is utilized to determine the optimal sliding surface and the sliding control law to improve performance of SMC. The proposed control strategy (SMC_GA_CMAC) is compared with three other types of approaches, that is, conventional SMC without optimization, optimal SMC with GA (SMC_GA), and SMC with CMAC compensation (SMC_CMAC), all of which are employed to track the desired joint angular position which is deduced from Clinical Gait Analysis (CGA) data. Position tracking performance is investigated with cosimulation using ADAMS and MATLAB/SIMULINK in two cases, of which the first case is without disturbances while the second case is with a bounded disturbance. The cosimulation results show the effectiveness of the proposed control strategy which can be employed in similar exoskeleton systems. PMID:27069353

  14. Robust Sliding Mode Control Based on GA Optimization and CMAC Compensation for Lower Limb Exoskeleton.

    PubMed

    Long, Yi; Du, Zhi-Jiang; Wang, Wei-Dong; Dong, Wei

    2016-01-01

    A lower limb assistive exoskeleton is designed to help operators walk or carry payloads. The exoskeleton is required to shadow human motion intent accurately and compliantly to prevent incoordination. If the user's intention is estimated accurately, a precise position control strategy will improve collaboration between the user and the exoskeleton. In this paper, a hybrid position control scheme, combining sliding mode control (SMC) with a cerebellar model articulation controller (CMAC) neural network, is proposed to control the exoskeleton to react appropriately to human motion intent. A genetic algorithm (GA) is utilized to determine the optimal sliding surface and the sliding control law to improve performance of SMC. The proposed control strategy (SMC_GA_CMAC) is compared with three other types of approaches, that is, conventional SMC without optimization, optimal SMC with GA (SMC_GA), and SMC with CMAC compensation (SMC_CMAC), all of which are employed to track the desired joint angular position which is deduced from Clinical Gait Analysis (CGA) data. Position tracking performance is investigated with cosimulation using ADAMS and MATLAB/SIMULINK in two cases, of which the first case is without disturbances while the second case is with a bounded disturbance. The cosimulation results show the effectiveness of the proposed control strategy which can be employed in similar exoskeleton systems.

  15. Stratospheric constituent distributions from balloon-based limb thermal emission measurements

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Kunde, Vigil G.

    1990-01-01

    This research task deals with an analysis of infrared thermal emission observations of the Earth's atmosphere for determination of trace constituent distributions. Infrared limb thermal emission spectra in the 700-2000 cm(exp -1) region were obtained with a liquid nitrogen cooled Michelson interferometer-spectrometer (SIRIS) on a balloon flight launched from Palestine, Texas, at nighttime on September 15-16, 1986. An important objective of this work is to obtain simultaneously measured vertical mixing ratio profiles of O3, H2O, N2O, NO2, N2O5, HNO3 and ClONO2 and compare with measurements made with a variety of techniques by other groups as well as with photochemical model calculations. A portion of the observed spectra obtained by SIRIS from the balloon flight on September 15-16, 1986, has been analyzed with a focus on calculation of the total nighttime odd nitrogen budget from the simultaneously measured profiles of important members of the NO(sub x) family. The measurements permit first direct determination of the nighttime total odd nitrogen concentrations NO(sub y) and the partitioning of the important elements of the NO(sub x) family.

  16. First study towards linear control of an upper-limb neuroprosthesis with an EEG-based Brain-Computer Interface.

    PubMed

    Pascual, Javier; Velasco-Alvarez, Francisco; Muller, Klaus-Robert; Vidaurre, Carmen

    2012-01-01

    In this study we show how healthy subjects are able to use a non-invasive Motor Imagery (MI)-based Brain Computer Interface (BCI) to achieve linear control of an upper-limb neuromuscular electrical stimulation (NMES) controlled neuroprosthesis in a simple binary target selection task. Linear BCI control can be achieved if two motor imagery classes can be discriminated with a reliability over 80% in single trial. The results presented in this work show that there was no significant loss of performance using the neuroprosthesis in comparison to MI where no stimulation was present. However, it is remarkable how different the experience of the users was in the same experiment. The stimulation either provoked a positive reinforcement feedback, or prevented the user from concentrating in the task.

  17. The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI).

    PubMed

    Mills, Joseph L; Conte, Michael S; Armstrong, David G; Pomposelli, Frank B; Schanzer, Andres; Sidawy, Anton N; Andros, George

    2014-01-01

    Critical limb ischemia, first defined in 1982, was intended to delineate a subgroup of patients with a threatened lower extremity primarily because of chronic ischemia. It was the intent of the original authors that patients with diabetes be excluded or analyzed separately. The Fontaine and Rutherford Systems have been used to classify risk of amputation and likelihood of benefit from revascularization by subcategorizing patients into two groups: ischemic rest pain and tissue loss. Due to demographic shifts over the last 40 years, especially a dramatic rise in the incidence of diabetes mellitus and rapidly expanding techniques of revascularization, it has become increasingly difficult to perform meaningful outcomes analysis for patients with threatened limbs using these existing classification systems. Particularly in patients with diabetes, limb threat is part of a broad disease spectrum. Perfusion is only one determinant of outcome; wound extent and the presence and severity of infection also greatly impact the threat to a limb. Therefore, the Society for Vascular Surgery Lower Extremity Guidelines Committee undertook the task of creating a new classification of the threatened lower extremity that reflects these important considerations. We term this new framework, the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. Risk stratification is based on three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI). The implementation of this classification system is intended to permit more meaningful analysis of outcomes for various forms of therapy in this challenging, but heterogeneous population.

  18. A 2-axis Polydimethylsiloxane (PDMS) based electromagnetic MEMS scanning mirror for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Kim, Sehui; Lee, Changho; Kim, Jin Young; Lim, Geunbae; Kim, Jeehyun; Kim, Chulhong

    2016-03-01

    Optical coherence tomography (OCT) is a noninvasive imaging tool for visualizing cross-sectional images of biological tissues on a microscale. Various microelectromechanical system (MEMS) techniques have been applied to OCT for endoscopic catheters and handheld probes. Despite having several advantages such as compact sizes and high speeds for real-time imaging, the complexities of the fabrication processes and relatively high costs were bottlenecks for fast clinical translation and commercialization of the earlier MEMS scanners. To overcome these issues, we developed a 2-axis polydimethylsiloxane (PDMS)-based electromagnetic MEMS scanning mirror based on flexible, cost-effective, and handleable PDMS. The size of this MEMS scanner was 15 × 15 × 15 mm3. To realize the characteristics of the scanner, we obtained the DC/AC responses and scanning patterns. The measured maximum scanning angles were 16.6° and 11.6° along the X and Y axes, respectively. The resonance frequencies were 82 and 57 Hz along the X and Y axes, respectively. The scanning patterns (raster and Lissajous scan patterns) are also demonstrated by controlling the frequency and amplitude. Finally, we showed the in vivo 2D-OCT images of human fingers by using a spectral domain OCT system with a PDMSbased MEMS scanning mirror. We then reconstructed the 3D images of human fingers. The obtained field of view was 8 × 8 mm2. The PDMS-based MEMS scanning mirror has the potential to combine other optical modalities and be widely used in preclinical and clinical translation research.

  19. Review of P-scan computer-based ultrasonic inservice inspection system. Supplement 1

    SciTech Connect

    Harris, R.V. Jr.; Angel, L.J.

    1995-12-01

    This Supplement reviews the P-scan system, a computer-based ultrasonic system used for inservice inspection of piping and other components in nuclear power plants. The Supplement was prepared using the methodology described in detail in Appendix A of NUREG/CR-5985, and is based on one month of using the system in a laboratory. This Supplement describes and characterizes: computer system, ultrasonic components, and mechanical components; scanning, detection, digitizing, imaging, data interpretation, operator interaction, data handling, and record-keeping. It includes a general description, a review checklist, and detailed results of all tests performed.

  20. MEMS scanning laser projection based on high-Q vacuum packaged 2D-resonators

    NASA Astrophysics Data System (ADS)

    Hofmann, U.; Eisermann, C.; Quenzer, H.-J.; Janes, J.; Schroeder, C.; Schwarzelbach, O.; Jensen, B.; Ratzmann, L.; Giese, T.; Senger, F.; Hagge, J.; Weiss, M.; Wagner, B.; Benecke, W.

    2011-03-01

    Small size, low power consumption and the capability to produce sharp images without need of an objective make MEMS scanning laser based pico-projectors an attractive solution for embedded cell-phone projection displays. To fulfil the high image resolution demands the MEMS scanning mirror has to show large scan angles, a large mirror aperture size and a high scan frequency. An additional important requirement in pico-projector applications is to minimize power consumption of the MEMS scanner to enable a long video projection time. Typically high losses in power are caused by gas damping. For that reason Fraunhofer ISIT has established a fabrication process for 2D-MEMS mirrors that includes vacuum encapsulation on 8-inch wafers. Quality factors as high as 145,000 require dedicated closed loop phase control electronics to enable stable image projection even at rapidly changing laser intensities. A capacitive feedback signal is the basis for controlling the 2D MEMS oscillation and for synchronising the laser sources. This paper reports on fabrication of two-axis wafer level vacuum packaged scanning micromirrors and its use in a compact laser projection display. The paper presents different approaches of overcoming the well-known reflex problem of packaged MEMS scanning mirrors.

  1. a New Approach for Segmentation-Based Texturing of Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Lari, Z.; Habib, A.

    2015-02-01

    In recent years, laser scanning systems have been recognized as a fast and accurate technology for the acquisition of high density spatial data. The advent of these systems has reduced the cost and increased the availability of accurate 3D data for mapping, modelling, and monitoring applications. The original laser scanning data does not explicitly provide meaningful information about the characteristics of the scanned surfaces. Therefore, reliable processing procedures are applied for information extraction from these datasets. However, the derived surfaces through laser scanning data processing cannot be effectively interpreted due to the lack of spectral information. To resolve this problem, a new texturing procedure is introduced in this paper to improve the interpretability of laser scanning-derived surfaces using spectral information from overlapping imagery. In this texturing approach, individual planar regions, derived through a laser scanning data segmentation procedure, are textured using the available imagery. This texturing approach, which aims to overcome the computational inefficiency of the previously-developed point-based texturing techniques, is implemented in three steps. In the first step, the visibility of the segmented planar regions in the available imagery is checked and a list of appropriate images for texturing each planar region is established. An occlusion detection procedure is then performed to identify the parts of the segmented regions which are occluding/being occluded by other regions in the field of view of the utilized images. In the second step, visible parts of planar regions are decomposed into parts which should be textured using individual images. Finally, a rendering procedure is performed to texture these parts using available images. Experimental results from real laser scanning dataset and overlapping imagery demonstrate the feasibility of the proposed approach for texturing laser scanning-derived surfaces using images.

  2. Rehabilitation assessment for lower limb disability based on multi-disciplinary approaches.

    PubMed

    Ai, Qing Song; Chen, Ling; Liu, Quan; Zou, Lin

    2014-06-01

    Low limb rehabilitation training is recognized as a very effective technique to facilitate body recovery. To make rehabilitation more efficient, we need to monitor the whole progress and detect how well the patient improves. The physician could make an optimal treatment plan according to the patient's improvement only when the patient's condition is correctly evaluated. Also, it is essential to provide a rehabilitation assessment system which would enable more accurate tracking of patient's status and minimize the requirement of time-consuming manual evaluations conducted by skilled person. Traditionally, clinical rehabilitation assessment is performed manually, which is not only coarse but also time-consuming. In this paper, we propose an objective, quantitative and manual-independent assessment system for lower extremity rehabilitation. Four predictive variables, i.e. rang of motion (ROM), movement smoothness, trajectory error, and improved L-Z complexity of electromyographic signal (EMG), are explored besides conventional clinical assessment scales. A cost-effective and wearable human-independent device which mainly consists of two sensors (MPU6050 and HMC5883L), is developed to measure the ROM, movement smoothness and trajectory error. What's more, a 3D leg model is employed to visualize the leg motion in real-time on PC screen to increase the entertainment. Those physical quantities are more sensitive at the early stage of rehabilitation. And when the basic body function is recovered, the subtle rehabilitation improvement can only be detected by the intrinsic EMG signal. Therefore an improved L-Z complexity of EMG is applied to combine with physical assessment metrics. Compared with traditional L-Z complexity, the improved one proposed in this paper could reflect more precisely the underlying property of EMG signal. The future work is to integrate all the evaluation metrics, thus we introduce a BP network to quantize a final assessment outcome.

  3. Simulation of Upper Limb Movements

    NASA Astrophysics Data System (ADS)

    Uherčík, Filip; Hučko, Branislav

    2011-12-01

    The paper deals with controlling an upper limb prosthesis based on the measurement of myoelectric signals (MES) while drinking. MES signals have been measured on healthy limbs to obtain the same response for the prosthesis. To simulate the drinking motion of a healthy upper limb, the program ADAMS was used, with all degrees of freedom and a hand after trans-radial amputation with an existing hand prosthesis. Modification of the simulation has the exact same logic of control, where the muscle does not have to be strenuous all the time, but it is the impulse of the muscle which drives the motor even though the impulse disappears and passed away.

  4. Autoblocker: a system for detecting and blocking of network scanning based on analysis of netflow data

    SciTech Connect

    Bobyshev, A.; Lamore, D.; Demar, P.; /Fermilab

    2004-12-01

    In a large campus network, such at Fermilab, with tens of thousands of nodes, scanning initiated from either outside of or within the campus network raises security concerns. This scanning may have very serious impact on network performance, and even disrupt normal operation of many services. In this paper we introduce a system for detecting and automatic blocking excessive traffic of different kinds of scanning, DoS attacks, virus infected computers. The system, called AutoBlocker, is a distributed computing system based on quasi-real time analysis of network flow data collected from the border router and core switches. AutoBlocker also has an interface to accept alerts from IDS systems (e.g. BRO, SNORT) that are based on other technologies. The system has multiple configurable alert levels for the detection of anomalous behavior and configurable trigger criteria for automated blocking of scans at the core or border routers. It has been in use at Fermilab for about 2 years, and has become a very valuable tool to curtail scan activity within the Fermilab campus network.

  5. Cantilevered bimorph-based scanner for high speed atomic force microscopy with large scanning range.

    PubMed

    Zhou, Yusheng; Shang, Guangyi; Cai, Wei; Yao, Jun-en

    2010-05-01

    A cantilevered bimorph-based resonance-mode scanner for high speed atomic force microscope (AFM) imaging is presented. The free end of the bimorph is used for mounting a sample stage and the other one of that is fixed on the top of a conventional single tube scanner. High speed scanning is realized with the bimorph-based scanner vibrating at resonant frequency driven by a sine wave voltage applied to one piezolayer of the bimorph, while slow scanning is performed by the tube scanner. The other piezolayer provides information on vibration amplitude and phase of the bimorph itself simultaneously, which is used for real-time data processing and image calibration. By adjusting the free length of the bimorph, the line scan rate can be preset ranging from several hundred hertz to several kilohertz, which would be beneficial for the observation of samples with different properties. Combined with a home-made AFM system and a commercially available data acquisition card, AFM images of various samples have been obtained, and as an example, images of the silicon grating taken at a line rate of 1.5 kHz with the scan size of 20 microm are given. By manually moving the sample of polished Al foil surface while scanning, the capability of dynamic imaging is demonstrated.

  6. Two Simple Classroom Demonstrations for Scanning Probe Microscopy Based on a Macroscopic Analogy

    ERIC Educational Resources Information Center

    Hajkova, Zdenka; Fejfar, Antonin; Smejkal, Petr

    2013-01-01

    This article describes two simple classroom demonstrations that illustrate the principles of scanning probe microscopy (SPM) based on a macroscopic analogy. The analogy features the bumps in an egg carton to represent the atoms on a chemical surface and a probe that can be represented by a dwarf statue (illustrating an origin of the prefix…

  7. Non-invasive Assessment of Lower Limb Geometry and Strength Using Hip Structural Analysis and Peripheral Quantitative Computed Tomography: A Population-Based Comparison.

    PubMed

    Litwic, A E; Clynes, M; Denison, H J; Jameson, K A; Edwards, M H; Sayer, A A; Taylor, P; Cooper, C; Dennison, E M

    2016-02-01

    Hip fracture is the most significant complication of osteoporosis in terms of mortality, long-term disability and decreased quality of life. In the recent years, different techniques have been developed to assess lower limb strength and ultimately fracture risk. Here we examine relationships between two measures of lower limb bone geometry and strength; proximal femoral geometry and tibial peripheral quantitative computed tomography. We studied a sample of 431 women and 488 men aged in the range 59-71 years. The hip structural analysis (HSA) programme was employed to measure the structural geometry of the left hip for each DXA scan obtained using a Hologic QDR 4500 instrument while pQCT measurements of the tibia were obtained using a Stratec 2000 instrument in the same population. We observed strong sex differences in proximal femoral geometry at the narrow neck, intertrochanteric and femoral shaft regions. There were significant (p < 0.001) associations between pQCT-derived measures of bone geometry (tibial width; endocortical diameter and cortical thickness) and bone strength (strength strain index) with each corresponding HSA variable (all p < 0.001) in both men and women. These results demonstrate strong correlations between two different methods of assessment of lower limb bone strength: HSA and pQCT. Validation in prospective cohorts to study associations of each with incident fracture is now indicated.

  8. Keypoint-based 4-Points Congruent Sets - Automated marker-less registration of laser scans

    NASA Astrophysics Data System (ADS)

    Theiler, Pascal Willy; Wegner, Jan Dirk; Schindler, Konrad

    2014-10-01

    We propose a method to automatically register two point clouds acquired with a terrestrial laser scanner without placing any markers in the scene. What makes this task challenging are the strongly varying point densities caused by the line-of-sight measurement principle, and the huge amount of data. The first property leads to low point densities in potential overlap areas with scans taken from different viewpoints while the latter calls for highly efficient methods in terms of runtime and memory requirements. A crucial yet largely unsolved step is the initial coarse alignment of two scans without any simplifying assumptions, that is, point clouds are given in arbitrary local coordinates and no knowledge about their relative orientation is available. Once coarse alignment has been solved, scans can easily be fine-registered with standard methods like least-squares surface or Iterative Closest Point matching. In order to drastically thin out the original point clouds while retaining characteristic features, we resort to extracting 3D keypoints. Such clouds of keypoints, which can be viewed as a sparse but nevertheless discriminative representation of the original scans, are then used as input to a very efficient matching method originally developed in computer graphics, called 4-Points Congruent Sets (4PCS) algorithm. We adapt the 4PCS matching approach to better suit the characteristics of laser scans. The resulting Keypoint-based 4-Points Congruent Sets (K-4PCS) method is extensively evaluated on challenging indoor and outdoor scans. Beyond the evaluation on real terrestrial laser scans, we also perform experiments with simulated indoor scenes, paying particular attention to the sensitivity of the approach with respect to highly symmetric scenes.

  9. Geometric super-resolved imaging based upon axial scanning and phase retrieval.

    PubMed

    Borkowski, Amikam; Marom, Emanuel; Zalevsky, Zeev

    2014-06-20

    In this paper, we propose a new geometric super-resolving approach that overcomes the geometric resolution reduction caused by the spatially large pixels of the detector array. The improvement process is obtained by applying an axial scanning procedure. In the scanning process, several images are captured corresponding to focus applied at several axial planes. By applying an iterative Gerchberg-Saxton-based algorithm, we managed to retrieve the phase and to reconstruct the original high-resolution image from the captured set of low-resolution images. In addition, the paper also presents a numerically efficient algorithm to compute the free space Fresnel integral.

  10. Radar Scan Strategies for the Patrick Air Force Base Weather Surveillance Radar, Model-74C, Replacement

    NASA Technical Reports Server (NTRS)

    Short, David

    2008-01-01

    The 45th Weather Squadron (45 WS) is replacing the Weather Surveillance Radar, Model 74C (WSR-74C) at Patrick Air Force Base (PAFB), with a Doppler, dual polarization radar, the Radtec 43/250. A new scan strategy is needed for the Radtec 43/250, to provide high vertical resolution data over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) launch pads, while taking advantage of the new radar's advanced capabilities for detecting severe weather phenomena associated with convection within the 45 WS area of responsibility. The Applied Meteorology Unit (AMU) developed several scan strategies customized for the operational needs of the 45 WS. The AMU also developed a plan for evaluating the scan strategies in the period prior to operational acceptance, currently scheduled for November 2008.

  11. Emulation and design of terahertz reflection-mode confocal scanning microscopy based on virtual pinhole

    NASA Astrophysics Data System (ADS)

    Yang, Yong-fa; Li, Qi

    2014-12-01

    In the practical application of terahertz reflection-mode confocal scanning microscopy, the size of detector pinhole is an important factor that determines the performance of spatial resolution characteristic of the microscopic system. However, the use of physical pinhole brings some inconvenience to the experiment and the adjustment error has a great influence on the experiment result. Through reasonably selecting the parameter of matrix detector virtual pinhole (VPH), it can efficiently approximate the physical pinhole. By using this approach, the difficulty of experimental calibration is reduced significantly. In this article, an imaging scheme of terahertz reflection-mode confocal scanning microscopy that is based on the matrix detector VPH is put forward. The influence of detector pinhole size on the axial resolution of confocal scanning microscopy is emulated and analyzed. Then, the parameter of VPH is emulated when the best axial imaging performance is reached.

  12. Scanning-free BOTDA based on ultra-fine digital optical frequency comb.

    PubMed

    Jin, Chao; Guo, Nan; Feng, Yuanhua; Wang, Liang; Liang, Hao; Li, Jianping; Li, Zhaohui; Yu, Changyuan; Lu, Chao

    2015-02-23

    We realize a scanning-free Brillouin optical time domain analyzer (BOTDA) based on an ultra-fine digital optical frequency comb (DOFC) with 1.95MHz frequency spacing and 2GHz bandwidth. The DOFC can be used to reconstruct the Brillouin gain spectrum (BGS) and locate the Brillouin frequency shift (BFS) without frequency scanning and thus can improve the measurement speed about 100 times compared with the conventional BOTDA. This scanning-free BOTDA scheme has also been demonstrated experimentally with 51.2m spatial resolution over 10km standard single mode fiber (SSMF) and with resolution of 1.5°C for temperature and 43.3με for strain measurement respectively.

  13. Learning-based scan plane identification from fetal head ultrasound images

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Annangi, Pavan; Gupta, Mithun; Yu, Bing; Padfield, Dirk; Banerjee, Jyotirmoy; Krishnan, Kajoli

    2012-03-01

    Acquisition of a clinically acceptable scan plane is a pre-requisite for ultrasonic measurement of anatomical features from B-mode images. In obstetric ultrasound, measurement of gestational age predictors, such as biparietal diameter and head circumference, is performed at the level of the thalami and cavum septum pelucidi. In an accurate scan plane, the head can be modeled as an ellipse, the thalami looks like a butterfly, the cavum appears like an empty box and the falx is a straight line along the major axis of a symmetric ellipse inclined either parallel to or at small angles to the probe surface. Arriving at the correct probe placement on the mother's belly to obtain an accurate scan plane is a task of considerable challenge especially for a new user of ultrasound. In this work, we present a novel automated learning-based algorithm to identify an acceptable fetal head scan plane. We divide the problem into cranium detection and a template matching to capture the composite "butterfly" structure present inside the head, which mimics the visual cues used by an expert. The algorithm uses the stateof- the-art Active Appearance Models techniques from the image processing and computer vision literature and tie them to presence or absence of the inclusions within the head to automatically compute a score to represent the goodness of a scan plane. This automated technique can be potentially used to train and aid new users of ultrasound.

  14. Flexible polygon-mirror based laser scanning microscope platform for multiphoton in-vivo imaging.

    PubMed

    Li, Y X; Gautam, V; Brüstle, A; Cockburn, I A; Daria, V R; Gillespie, C; Gaus, K; Alt, C; Lee, W M

    2017-02-06

    Commercial microscopy systems make use of tandem scanning i.e. either slow or fast scanning. We constructed, for the first time, an advanced control system capable of delivering a dynamic line scanning speed ranging from 2.7 kHz to 27 kHz and achieve variable frame rates from 5 Hz to 50 Hz (512 × 512). The dynamic scanning ability is digitally controlled by a new customized open-source software named PScan1.0. This permits manipulation of scanning rates either to gain higher fluorescence signal at slow frame rate without increasing laser power or increase frame rates to capture high speed events. By adjusting imaging speed from 40 Hz to 160 Hz, we capture a range of calcium waves and transient peaks from soma and dendrite of single fluorescence neuron (CAL-520AM). Motion artifacts arising from respiratory and cardiac motion in small animal imaging reduce quality of real-time images of single cells in-vivo. An image registration algorithm, integrated with PScan1.0, was shown to perform both real time and post-processed motion correction. The improvement is verified by quantification of blood flow rates. This work describes all the steps necessary to develop a high performance and flexible polygon-mirror based multiphoton microscope system for in-vivo biological imaging.

  15. Immediate effects of a brief mindfulness-based body scan on patients with chronic pain.

    PubMed

    Ussher, Michael; Spatz, Amy; Copland, Claire; Nicolaou, Andrew; Cargill, Abbey; Amini-Tabrizi, Nina; McCracken, Lance M

    2014-02-01

    Mindfulness-based stress reduction (MBSR) has benefits for those with chronic pain. MBSR typically entails an intensive 8-week intervention. The effects of very brief mindfulness interventions are unknown. Among those with chronic pain, the immediate effects of a 10 min mindfulness-based body scan were compared with a control intervention. Fifty-five adult outpatients were randomly assigned to either: (1) mindfulness-based body scan (n = 27) or (2) a reading about natural history (control group, n = 28), provided via a 10 min audio-recording. Interventions were delivered twice across 24 h; once in the clinic and once in participants' 'normal' environment. Immediately before and after listening to the recording, participants rated pain severity, pain related distress, perceived ability for daily activities, perceived likelihood of pain interfering with social relations, and mindfulness. In the clinic, there was a significant reduction in ratings for pain related distress and for pain interfering with social relations for the body scan group compared with the control group (p = 0.005; p = 0.036, respectively). In the normal environment none of the ratings were significantly different between the groups. These data suggest that, in a clinic setting, a brief body scan has immediate benefits for those experiencing chronic pain. These benefits need to be confirmed in the field.

  16. Theoretical study of carbon-based tips for scanning tunnelling microscopy.

    PubMed

    González, C; Abad, E; Dappe, Y J; Cuevas, J C

    2016-03-11

    Motivated by recent experiments, we present here a detailed theoretical analysis of the use of carbon-based conductive tips in scanning tunnelling microscopy. In particular, we employ ab initio methods based on density functional theory to explore a graphitic, an amorphous carbon and two diamond-like tips for imaging with a scanning tunnelling microscope (STM), and we compare them with standard metallic tips made of gold and tungsten. We investigate the performance of these tips in terms of the corrugation of the STM images acquired when scanning a single graphene sheet. Moreover, we analyse the impact of the tip-sample distance and show that it plays a fundamental role in the resolution and symmetry of the STM images. We also explore in depth how the adsorption of single atoms and molecules in the tip apexes modifies the STM images and demonstrate that, in general, it leads to an improved image resolution. The ensemble of our results provides strong evidence that carbon-based tips can significantly improve the resolution of STM images, as compared to more standard metallic tips, which may open a new line of research in scanning tunnelling microscopy.

  17. Home-based neurologic music therapy for upper limb rehabilitation with stroke patients at community rehabilitation stage—a feasibility study protocol

    PubMed Central

    Street, Alexander J.; Magee, Wendy L.; Odell-Miller, Helen; Bateman, Andrew; Fachner, Jorg C.

    2015-01-01

    Background: Impairment of upper limb function following stroke is more common than lower limb impairment and is also more resistant to treatment. Several lab-based studies with stroke patients have produced statistically significant gains in upper limb function when using musical instrument playing and techniques where rhythm acts as an external time-keeper for the priming and timing of upper limb movements. Methods: For this feasibility study a small sample size of 14 participants (3–60 months post stroke) has been determined through clinical discussion between the researcher and study host in order to test for management, feasibility and effects, before planning a larger trial determined through power analysis. A cross-over design with five repeated measures will be used, whereby participants will be randomized into either a treatment (n = 7) or wait list control (n = 7) group. Intervention will take place twice weekly over 6 weeks. The ARAT and 9HPT will be used to measure for quantitative gains in arm function and finger dexterity, pre/post treatment interviews will serve to investigate treatment compliance and tolerance. A lab based EEG case comparison study will be undertaken to explore audio-motor coupling, brain connectivity and neural reorganization with this intervention, as evidenced in similar studies. Discussion: Before evaluating the effectiveness of a home-based intervention in a larger scale study, it is important to assess whether implementation of the trial methodology is feasible. This study investigates the feasibility, efficacy and patient experience of a music therapy treatment protocol comprising a chart of 12 different instrumental exercises and variations, which aims at promoting measurable changes in upper limb function in hemiparetic stroke patients. The study proposes to examine several new aspects including home-based treatment and dosage, and will provide data on recruitment, adherence and variability of outcomes. PMID:26441586

  18. Botulinum Toxin Type a Injection, Followed by Home-Based Functional Training for Upper Limb Hemiparesis after Stroke

    ERIC Educational Resources Information Center

    Takekawa, Toru; Kakuda, Wataru; Taguchi, Kensuke; Ishikawa, Atsushi; Sase, Yousuke; Abo, Masahiro

    2012-01-01

    Botulinum toxin type A (BoNT-A) has been reported to be an effective treatment for limb spasticity after stroke. However, the reduction in the spasticity after BoNT-A injection alone does not ensure an improvement in the active motor function of the affected limb. The aim of this study was to clarify the clinical effects of a BoNT-A injection,…

  19. Direct absorbed dose to water determination based on water calorimetry in scanning proton beam delivery

    SciTech Connect

    Sarfehnia, A.; Clasie, B.; Chung, E.; Lu, H. M.; Flanz, J.; Cascio, E.; Engelsman, M.; Paganetti, H.; Seuntjens, J.

    2010-07-15

    Purpose: The aim of this manuscript is to describe the direct measurement of absolute absorbed dose to water in a scanned proton radiotherapy beam using a water calorimeter primary standard. Methods: The McGill water calorimeter, which has been validated in photon and electron beams as well as in HDR {sup 192}Ir brachytherapy, was used to measure the absorbed dose to water in double scattering and scanning proton irradiations. The measurements were made at the Massachusetts General Hospital proton radiotherapy facility. The correction factors in water calorimetry were numerically calculated and various parameters affecting their magnitude and uncertainty were studied. The absorbed dose to water was compared to that obtained using an Exradin T1 Chamber based on the IAEA TRS-398 protocol. Results: The overall 1-sigma uncertainty on absorbed dose to water amounts to 0.4% and 0.6% in scattered and scanned proton water calorimetry, respectively. This compares to an overall uncertainty of 1.9% for currently accepted IAEA TRS-398 reference absorbed dose measurement protocol. The absorbed dose from water calorimetry agrees with the results from TRS-398 well to within 1-sigma uncertainty. Conclusions: This work demonstrates that a primary absorbed dose standard based on water calorimetry is feasible in scattered and scanned proton beams.

  20. Scan-based volume animation driven by locally adaptive articulated registrations.

    PubMed

    Rhee, Taehyun; Lewis, J P; Neumann, Ulrich; Nayak, Krishna S

    2011-03-01

    This paper describes a complete system to create anatomically accurate example-based volume deformation and animation of articulated body regions, starting from multiple in vivo volume scans of a specific individual. In order to solve the correspondence problem across volume scans, a template volume is registered to each sample. The wide range of pose variations is first approximated by volume blend deformation (VBD), providing proper initialization of the articulated subject in different poses. A novel registration method is presented to efficiently reduce the computation cost while avoiding strong local minima inherent in complex articulated body volume registration. The algorithm highly constrains the degrees of freedom and search space involved in the nonlinear optimization, using hierarchical volume structures and locally constrained deformation based on the biharmonic clamped spline. Our registration step establishes a correspondence across scans, allowing a data-driven deformation approach in the volume domain. The results provide an occlusion-free person-specific 3D human body model, asymptotically accurate inner tissue deformations, and realistic volume animation of articulated movements driven by standard joint control estimated from the actual skeleton. Our approach also addresses the practical issues arising in using scans from living subjects. The robustness of our algorithms is tested by their applications on the hand, probably the most complex articulated region in the body, and the knee, a frequent subject area for medical imaging due to injuries.

  1. A Fourier Transform Spectrometer Based on an Electrothermal MEMS Mirror with Improved Linear Scan Range

    PubMed Central

    Wang, Wei; Chen, Jiapin; Zivkovic, Aleksandar. S.; Xie, Huikai

    2016-01-01

    A Fourier transform spectrometer (FTS) that incorporates a closed-loop controlled, electrothermally actuated microelectromechanical systems (MEMS) micromirror is proposed and experimentally verified. The scan range and the tilting angle of the mirror plate are the two critical parameters for MEMS-based FTS. In this work, the MEMS mirror with a footprint of 4.3 mm × 3.1 mm is based on a modified lateral-shift-free (LSF) bimorph actuator design with large piston and reduced tilting. Combined with a position-sensitive device (PSD) for tilt angle sensing, the feedback controlled MEMS mirror generates a 430 µm stable linear piston scan with the mirror plate tilting angle less than ±0.002°. The usable piston scan range is increased to 78% of the MEMS mirror’s full scan capability, and a spectral resolution of 0.55 nm at 531.9 nm wavelength, has been achieved. It is a significant improvement compared to the prior work. PMID:27690047

  2. Temporal subtraction system on torso FDG-PET scans based on statistical image analysis

    NASA Astrophysics Data System (ADS)

    Shimizu, Yusuke; Hara, Takeshi; Fukuoka, Daisuke; Zhou, Xiangrong; Muramatsu, Chisako; Ito, Satoshi; Hakozaki, Kenta; Kumita, Shin-ichiro; Ishihara, Kei-ichi; Katafuchi, Tetsuro; Fujita, Hiroshi

    2013-02-01

    Diagnostic imaging on FDG-PET scans was often used to evaluate chemotherapy results of cancer patients. Radiologists compare the changes of lesions' activities between previous and current examinations for the evaluation. The purpose of this study was to develop a new computer-aided detection (CAD) system with temporal subtraction technique for FDGPET scans and to show the fundamental usefulness based on an observer performance study. Z-score mapping based on statistical image analysis was newly applied to the temporal subtraction technique. The subtraction images can be obtained based on the anatomical standardization results because all of the patients' scans were deformed into standard body shape. An observer study was performed without and with computer outputs to evaluate the usefulness of the scheme by ROC (receiver operating characteristics) analysis. Readers responded as confidence levels on a continuous scale from absolutely no change to definitely change between two examinations. The recognition performance of the computer outputs for the 43 pairs was 96% sensitivity with 31.1 false-positive marks per scan. The average of area-under-the-ROC-curve (AUC) from 4 readers in the observer performance study was increased from 0.85 without computer outputs to 0.90 with computer outputs (p=0.0389, DBM-MRMC). The average of interpretation time was slightly decreased from 42.11 to 40.04 seconds per case (p=0.625, Wilcoxon test). We concluded that the CAD system for torso FDG-PET scans with temporal subtraction technique might improve the diagnostic accuracy of radiologist in cancer therapy evaluation.

  3. Laser-based ultrasonic inspection with a fiber-coupled scanning Cassegrain system.

    PubMed

    McKie, Andrew D W; Addison, Robert C

    2002-12-01

    State-of-the-art integrally stiffened composite materials, manufactured for use in the next generation of commercial and military aircraft, are increasingly being used for structural components such as wings and fuselages. However, the complexity of the manufacturing processes can produce small variations in the shape of integrally stiffened composite structures. Thus, a priori knowledge of the nominal part shape often does not provide sufficient accuracy to allow an automated conventional ultrasonic inspection. In contrast, automated inspections of integrally stiffened structures can be performed using laser-based ultrasound techniques since a priori knowledge of the nominal part shape is adequate to scan the laser beams over the structure. This paper addresses the issues associated with the extension of laser-based ultrasonics to inspections in remote and limited access areas, and describes the implementation of a fiber-based remote and limited access LBU inspection system based upon a Cassegrain scanning and optical collection system. The ability to quickly and directly manipulate flexible low mass optical fibers equipped with specialized endoscopic scanning optics make fiber systems an attractive method for the development of limited and remote access inspection systems. The Cassegrain optical system is described in detail and both numerical and experimental validation of the system operational characteristics are presented.

  4. A hard-threshold based sparse inverse imaging algorithm for optical scanning holography reconstruction

    NASA Astrophysics Data System (ADS)

    Zhao, Fengjun; Qu, Xiaochao; Zhang, Xing; Poon, Ting-Chung; Kim, Taegeun; Kim, You Seok; Liang, Jimin

    2012-03-01

    The optical imaging takes advantage of coherent optics and has promoted the development of visualization of biological application. Based on the temporal coherence, optical coherence tomography can deliver three-dimensional optical images with superior resolutions, but the axial and lateral scanning is a time-consuming process. Optical scanning holography (OSH) is a spatial coherence technique which integrates three-dimensional object into a two-dimensional hologram through a two-dimensional optical scanning raster. The advantages of high lateral resolution and fast image acquisition offer it a great potential application in three-dimensional optical imaging, but the prerequisite is the accurate and practical reconstruction algorithm. Conventional method was first adopted to reconstruct sectional images and obtained fine results, but some drawbacks restricted its practicality. An optimization method based on 2 l norm obtained more accurate results than that of the conventional methods, but the intrinsic smooth of 2 l norm blurs the reconstruction results. In this paper, a hard-threshold based sparse inverse imaging algorithm is proposed to improve the sectional image reconstruction. The proposed method is characterized by hard-threshold based iterating with shrinkage threshold strategy, which only involves lightweight vector operations and matrix-vector multiplication. The performance of the proposed method has been validated by real experiment, which demonstrated great improvement on reconstruction accuracy at appropriate computational cost.

  5. Adaptive circle-ellipse fitting method for estimating tree diameter based on single terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Bu, Guochao; Wang, Pei

    2016-04-01

    Terrestrial laser scanning (TLS) has been used to extract accurate forest biophysical parameters for inventory purposes. The diameter at breast height (DBH) is a key parameter for individual trees because it has the potential for modeling the height, volume, biomass, and carbon sequestration potential of the tree based on empirical allometric scaling equations. In order to extract the DBH from the single-scan data of TLS automatically and accurately within a certain range, we proposed an adaptive circle-ellipse fitting method based on the point cloud transect. This proposed method can correct the error caused by the simple circle fitting method when a tree is slanted. A slanted tree was detected by the circle-ellipse fitting analysis, then the corresponding slant angle was found based on the ellipse fitting result. With this information, the DBH of the trees could be recalculated based on reslicing the point cloud data at breast height. Artificial stem data simulated by a cylindrical model of leaning trees and the scanning data acquired with the RIEGL VZ-400 were used to test the proposed adaptive fitting method. The results shown that the proposed method can detect the trees and accurately estimate the DBH for leaning trees.

  6. Self-guided clinical cases for medical students based on postmortem CT scans of cadavers.

    PubMed

    Bohl, Michael; Francois, Webster; Gest, Thomas

    2011-07-01

    In the summer of 2009, we began full body computed tomography (CT) scanning of the pre-embalmed cadavers in the University of Michigan Medical School (UMMS) dissection lab. We theorized that implementing web-based, self-guided clinical cases based on postmortem CT (PMCT) scans would result in increased student appreciation for the clinical relevance of anatomy, increased knowledge of cross-sectional anatomy, and increased ability to identify common pathologies on CT scans. The PMCT scan of each cadaver was produced as a DICOM dataset, and then converted into a Quicktime movie file using Osirix software. Clinical cases were researched and written by the authors, and consist of at least one Quicktime movie of a PMCT scan surrounded by a novel navigation interface. To assess the value of these clinical cases we surveyed medical students at UMMS who are currently using the clinical cases in their coursework. Students felt the clinical cases increased the clinical relevance of anatomy (mean response 7.77/10), increased their confidence finding anatomical structures on CT (7.00/10), and increased their confidence recognizing common pathologies on CT (6.17/10). Students also felt these clinical cases helped them synthesize material from numerous courses into an overall picture of a given disease process (7.01/10). These results support the conclusion that our clinical cases help to show students why the anatomy they are learning is foundational to their other coursework. We would recommend the use of similar clinical cases to any medical school utilizing cadaver dissection as a primary teaching method in anatomy education.

  7. The analysis of self-esteem based on patients` self-perception after Ilizarov limb lengthening treatment.

    PubMed

    Słomska, Beata; Pilarz, Eliza; Niedzielski, Kryspin Ryszard

    2012-08-09

    In the article there is shown the analysis of patients self-perception after the Ilizarov limb lenghening treatment due to inequality. 150 patients both sexes (78 girls and 72 boys) were tested between 1992 and 2003 in our center. The average age for girls at the time of follow-up was 19.5 years and 18.5 years for boys. In the survey there was used four point-scale SES by Irena Dzwokowska, Kinga Lachowicz-Tabaczek and Mariola Łagun which was based on Rosenberg work. The results were divided into two groups: low or high score. It was evaluated according to the table of standards which included people age and sex. Then the score was transformed into standard ten. For statistical calculations was used MicroSoft Excel spreadsheet. In the case of statistical studies was used Spss v.17.0. It was found that among survey respondents regardless of gender and age after the satisfactory completion of Ilizarov treatment patients gain a high level of self-assessment at 7 standard ten. The high self-esteem can predict the level of patients` comfort in many aspects of their lives. People with such a hight self-perception will experience more positive emotions and will be healthier and more active.

  8. FDA perspective on objective performance goals and clinical trial design for evaluating catheter-based treatment of critical limb ischemia.

    PubMed

    Kumar, Allison; Brooks, Steven S; Cavanaugh, Kenneth; Zuckerman, Bram

    2009-12-01

    The article by Conte et al.(1) on behalf of the Society for Vascular Surgery (SVS) in this issue of the Journal of Vascular Surgery provides guidelines for improving the consistency and interpretability of clinical trials intended to evaluate treatment options for patients with critical limb ischemia (CLI). This article identifies a number of key challenges with conducting and comparing CLI trials, including the wide spectrum of clinical presentations that CLI encompasses, the use of disparate eligibility criteria and endpoint measurements, and logistical and economic considerations that can limit study initiation and completion. The authors propose definitions for a number of performance goals derived from historical surgical literature as a means of reducing the negative impact of these factors. The current editorial reviews aspects of this proposal from the perspective of the authors in terms of their understanding of the statutory obligations of the U.S. Food and Drug Administration (FDA) to regulate the marketing of cardiovascular devices based on valid scientific evidence.

  9. Entropy-Based Registration of Point Clouds Using Terrestrial Laser Scanning and Smartphone GPS

    PubMed Central

    Chen, Maolin; Wang, Siying; Wang, Mingwei; Wan, Youchuan; He, Peipei

    2017-01-01

    Automatic registration of terrestrial laser scanning point clouds is a crucial but unresolved topic that is of great interest in many domains. This study combines terrestrial laser scanner with a smartphone for the coarse registration of leveled point clouds with small roll and pitch angles and height differences, which is a novel sensor combination mode for terrestrial laser scanning. The approximate distance between two neighboring scan positions is firstly calculated with smartphone GPS coordinates. Then, 2D distribution entropy is used to measure the distribution coherence between the two scans and search for the optimal initial transformation parameters. To this end, we propose a method called Iterative Minimum Entropy (IME) to correct initial transformation parameters based on two criteria: the difference between the average and minimum entropy and the deviation from the minimum entropy to the expected entropy. Finally, the presented method is evaluated using two data sets that contain tens of millions of points from panoramic and non-panoramic, vegetation-dominated and building-dominated cases and can achieve high accuracy and efficiency. PMID:28117693

  10. Entropy-Based Registration of Point Clouds Using Terrestrial Laser Scanning and Smartphone GPS.

    PubMed

    Chen, Maolin; Wang, Siying; Wang, Mingwei; Wan, Youchuan; He, Peipei

    2017-01-20

    Automatic registration of terrestrial laser scanning point clouds is a crucial but unresolved topic that is of great interest in many domains. This study combines terrestrial laser scanner with a smartphone for the coarse registration of leveled point clouds with small roll and pitch angles and height differences, which is a novel sensor combination mode for terrestrial laser scanning. The approximate distance between two neighboring scan positions is firstly calculated with smartphone GPS coordinates. Then, 2D distribution entropy is used to measure the distribution coherence between the two scans and search for the optimal initial transformation parameters. To this end, we propose a method called Iterative Minimum Entropy (IME) to correct initial transformation parameters based on two criteria: the difference between the average and minimum entropy and the deviation from the minimum entropy to the expected entropy. Finally, the presented method is evaluated using two data sets that contain tens of millions of points from panoramic and non-panoramic, vegetation-dominated and building-dominated cases and can achieve high accuracy and efficiency.

  11. MEMS-based non-rotatory circumferential scanning optical probe for endoscopic optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Xu, Yingshun; Singh, Janak; Siang, Teo Hui; Ramakrishna, Kotlanka; Premchandran, C. S.; Sheng, Chen Wei; Kuan, Chuah Tong; Chen, Nanguang; Olivo, Malini C.; Sheppard, Colin J. R.

    2007-07-01

    In this paper, we present a non-rotatory circumferential scanning optical probe integrated with a MEMS scanner for in vivo endoscopic optical coherence tomography (OCT). OCT is an emerging optical imaging technique that allows high resolution cross-sectional imaging of tissue microstructure. To extend its usage to endoscopic applications, a miniaturized optical probe based on Microelectromechanical Systems (MEMS) fabrication techniques is currently desired. A 3D electrothermally actuated micromirror realized using micromachining single crystal silicon (SCS) process highlights its very large angular deflection, about 45 degree, with low driving voltage for safety consideration. The micromirror is integrated with a GRIN lens into a waterproof package which is compatible with requirements for minimally invasive endoscopic procedures. To implement circumferential scanning substantially for diagnosis on certain pathological conditions, such as Barret's esophagus, the micromirror is mounted on 90 degree to optical axis of GRIN lens. 4 Bimorph actuators that are connected to the mirror on one end via supporting beams and springs are selected in this micromirror design. When actuators of the micromirror are driven by 4 channels of sinusoidal waveforms with 90 degree phase differences, beam focused by a GRIN is redirected out of the endoscope by 45 degree tilting mirror plate and achieve circumferential scanning pattern. This novel driving method making full use of very large angular deflection capability of our micromirror is totally different from previously developed or developing micromotor-like rotatory MEMS device for circumferential scanning.

  12. Microcomputer-based image processing system for CT/MRI scans: II. Expert system

    NASA Astrophysics Data System (ADS)

    Kwok, John C. K.; Yu, Peter K. N.; Cheng, Andrew Y. S.; Ho, Wai-Chin

    1991-06-01

    A microcomputer-based image processing system is used to digitize and process serial sections of CT/MRI scan and reconstruct three-dimensional images of brain structures and brain lesions. The images grabbed also serve as templates and different vital regions with different risk values are also traced out for 3D reconstruction. A knowledge-based system employing rule-based programming has been built to help identifying brain lesions and to help planning trajectory for operations. The volumes of the lesions are also automatically determined. Such system is very useful for medical skills archival, tumor size monitoring, survival and outcome forecasting, and consistent neurosurgical planning.

  13. Canoe game-based virtual reality training to improve trunk postural stability, balance, and upper limb motor function in subacute stroke patients: a randomized controlled pilot study.

    PubMed

    Lee, Myung-Mo; Shin, Doo-Chul; Song, Chang-Ho

    2016-07-01

    [Purpose] This study was aimed at investigating the preliminary therapeutic efficacy and usefulness of canoe game-based virtual reality training for stroke patients. [Subjects and Methods] Ten stroke patients were randomly assigned to an experimental group (EG; n=5) or a control group (CG; n=5). Patients in both groups participated in a conventional rehabilitation program, but those in the EG additionally participated in a 30-min canoe game-based virtual reality training program 3 days a week for 4 weeks. Therapeutic efficacy was assessed based on trunk postural stability, balance, and upper limb motor function. In addition, the usefulness of canoe game-based virtual reality training was assessed in the EG and therapist group (TG; n=20), which consisted of physical and occupational therapists, by using the System Usability Scale (SUS). [Results] Improvements in trunk postural stability, balance, and upper limb motor function were observed in the EG and CG, but were greater in the EG. The mean SUS scores in the EG and TG were 71 ± 5.2 and 74.2 ± 4.8, respectively. [Conclusion] Canoe game-based virtual reality training is an acceptable and effective intervention for improving trunk postural stability, balance, and upper limb motor function in stroke patients.

  14. Canoe game-based virtual reality training to improve trunk postural stability, balance, and upper limb motor function in subacute stroke patients: a randomized controlled pilot study

    PubMed Central

    Lee, Myung-Mo; Shin, Doo-Chul; Song, Chang-Ho

    2016-01-01

    [Purpose] This study was aimed at investigating the preliminary therapeutic efficacy and usefulness of canoe game-based virtual reality training for stroke patients. [Subjects and Methods] Ten stroke patients were randomly assigned to an experimental group (EG; n=5) or a control group (CG; n=5). Patients in both groups participated in a conventional rehabilitation program, but those in the EG additionally participated in a 30-min canoe game-based virtual reality training program 3 days a week for 4 weeks. Therapeutic efficacy was assessed based on trunk postural stability, balance, and upper limb motor function. In addition, the usefulness of canoe game-based virtual reality training was assessed in the EG and therapist group (TG; n=20), which consisted of physical and occupational therapists, by using the System Usability Scale (SUS). [Results] Improvements in trunk postural stability, balance, and upper limb motor function were observed in the EG and CG, but were greater in the EG. The mean SUS scores in the EG and TG were 71 ± 5.2 and 74.2 ± 4.8, respectively. [Conclusion] Canoe game-based virtual reality training is an acceptable and effective intervention for improving trunk postural stability, balance, and upper limb motor function in stroke patients. PMID:27512255

  15. Design of a MEMS-based retina scanning system for biometric authentication

    NASA Astrophysics Data System (ADS)

    Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Schelinski, Uwe; Grüger, Heinrich

    2014-05-01

    There is an increasing need for reliable authentication for a number of applications such as e commerce. Common authentication methods based on ownership (ID card) or knowledge factors (password, PIN) are often prone to manipulations and may therefore be not safe enough. Various inherence factor based methods like fingerprint, retinal pattern or voice identifications are considered more secure. Retina scanning in particular offers both low false rejection rate (FRR) and low false acceptance rate (FAR) with about one in a million. Images of the retina with its characteristic pattern of blood vessels can be made with either a fundus camera or laser scanning methods. The present work describes the optical design of a new compact retina laser scanner which is based on MEMS (Micro Electric Mechanical System) technology. The use of a dual axis micro scanning mirror for laser beam deflection enables a more compact and robust design compared to classical systems. The scanner exhibits a full field of view of 10° which corresponds to an area of 4 mm2 on the retinal surface surrounding the optical disc. The system works in the near infrared and is designed for use under ambient light conditions, which implies a pupil diameter of 1.5 mm. Furthermore it features a long eye relief of 30 mm so that it can be conveniently used by persons wearing glasses. The optical design requirements and the optical performance are discussed in terms of spot diagrams and ray fan plots.

  16. The use of virtual reality-based therapy to augment poststroke upper limb recovery

    PubMed Central

    Samuel, Geoffrey S; Choo, Min; Chan, Wai Yin; Kok, Stanley; Ng, Yee Sien

    2015-01-01

    Stroke remains one of the major causes of disability worldwide. This case report illustrates the complementary use of biomechanical and kinematic in-game markers, in addition to standard clinical outcomes, to comprehensively assess and track a patient’s disabilities. A 65-year-old patient was admitted for right-sided weakness and clinically diagnosed with acute ischaemic stroke. She participated in a short trial of standard stroke occupational therapy and physiotherapy with additional daily virtual reality (VR)-based therapy. Outcomes were tracked using kinematic data and conventional clinical assessments. Her Functional Independence Measure score improved from 87 to 113 and Fugl-Meyer motor score improved from 56 to 62, denoting clinically significant improvement. Corresponding kinematic analysis revealed improved hand path ratios and a decrease in velocity peaks. Further research is being undertaken to elucidate the optimal type, timing, setting and duration of VR-based therapy, as well as the use of neuropharmacological adjuncts. PMID:26243983

  17. Feature-Based Laser Scan Matching and Its Application for Indoor Mapping

    PubMed Central

    Li, Jiayuan; Zhong, Ruofei; Hu, Qingwu; Ai, Mingyao

    2016-01-01

    Scan matching, an approach to recover the relative position and orientation of two laser scans, is a very important technique for indoor positioning and indoor modeling. The iterative closest point (ICP) algorithm and its variants are the most well-known techniques for such a problem. However, ICP algorithms rely highly on the initial guess of the relative transformation, which will reduce its power for practical applications. In this paper, an initial-free 2D laser scan matching method based on point and line features is proposed. We carefully design a framework for the detection of point and line feature correspondences. First, distinct feature points are detected based on an extended 1D SIFT, and line features are extracted via a modified Split-and-Merge algorithm. In this stage, we also give an effective strategy for discarding unreliable features. The point and line features are then described by a distance histogram; the pairs achieving best matching scores are accepted as potential correct correspondences. The histogram cluster technique is adapted to filter outliers and provide an accurate initial value of the rigid transformation. We also proposed a new relative pose estimation method that is robust to outliers. We use the lq-norm (0 < q < 1) metric in this approach, in contrast to classic optimization methods whose cost function is based on the l2-norm of residuals. Extensive experiments on real data demonstrate that the proposed method is almost as accurate as ICPs and is initial free. We also show that our scan matching method can be integrated into a simultaneous localization and mapping (SLAM) system for indoor mapping. PMID:27517932

  18. An elastography method based on the scanning contact resonance of a piezoelectric cantilever

    SciTech Connect

    Fu, Ji; Li, Faxin

    2013-12-15

    Purpose: Most tissues may become significantly stiffer than their normal states when there are lesions inside. The tissue's modulus can then act as an identification parameter for clinic diagnosis of tumors or fibrosis, which leads to elastography. This study introduces a novel elastography method that can be used for modulus imaging of superficial organs. Methods: This method is based on the scanning contact-resonance of a unimorph piezoelectric cantilever. The cantilever vibrates in its bending mode with the tip pressed tightly on the sample. The contact resonance frequency of the cantilever-sample system is tracked at each scanning point, from which the sample's modulus can be derived based on a beam dynamic model and a contact mechanics model. Scanning is performed by a three-dimensional motorized stage and the whole system is controlled by a homemade software program based on LabVIEW. Results: Testing onin vitro beef tissues indicates that the fat and the muscle can be easily distinguished using this system, and the accuracy of the modulus measurement can be comparable with that of nanoindentation. Imaging on homemade gelatin phantoms shows that the depth information of the abnormalities can be qualitatively obtained by varying the pressing force. The detection limit of this elastography method is specially examined both experimentally and numerically. Results show that it can detect the typical lesions in superficial organs with the depth of several centimeters. The lateral resolution of this elastography method/system is better than 0.5 mm, and could be further enhanced by using more scanning points. Conclusions: The proposed elastography system can be regarded as a sensitive palpation robot, which may be very promising in early diagnosis of tumors in superficial organs such as breast and thyroid.

  19. UAV-borne lidar with MEMS mirror-based scanning capability

    NASA Astrophysics Data System (ADS)

    Kasturi, Abhishek; Milanovic, Veljko; Atwood, Bryan H.; Yang, James

    2016-05-01

    Firstly, we demonstrated a wirelessly controlled MEMS scan module with imaging and laser tracking capability which can be mounted and flown on a small UAV quadcopter. The MEMS scan module was reduced down to a small volume of <90mm x 60mm x 40mm, weighing less than 40g and consuming less than 750mW of power using a ~5mW laser. This MEMS scan module was controlled by a smartphone via Bluetooth while flying on a drone, and could project vector content, text, and perform laser based tracking. Also, a "point-and-range" LiDAR module was developed for UAV applications based on low SWaP (Size, Weight and Power) gimbal-less MEMS mirror beam-steering technology and off-the-shelf OEM LRF modules. For demonstration purposes of an integrated laser range finder module, we used a simple off-the-shelf OEM laser range finder (LRF) with a 100m range, +/-1.5mm accuracy, and 4Hz ranging capability. The LRFs receiver optics were modified to accept 20° of angle, matching the transmitter's FoR. A relatively large (5.0mm) diameter MEMS mirror with +/-10° optical scanning angle was utilized in the demonstration to maintain the small beam divergence of the module. The complete LiDAR prototype can fit into a small volume of <70mm x 60mm x 60mm, and weigh <50g when powered by the UAV's battery. The MEMS mirror based LiDAR system allows for ondemand ranging of points or areas within the FoR without altering the UAV's position. Increasing the LRF ranging frequency and stabilizing the pointing of the laser beam by utilizing the onboard inertial sensors and the camera are additional goals of the next design.

  20. Optimization of attenuation correction for positron emission tomography studies of thorax and pelvis using count-based transmission scans.

    PubMed

    Boellaard, R; van Lingen, A; van Balen, S C M; Lammertsma, A A

    2004-02-21

    The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image quality and more precise quantification than with fixed transmission scan duration. First, the relation between noise equivalent counts (NEC) of 10 min calibration transmission scans and rod source activity was determined over a period of 1.5 years. Second, the relation between transmission scan counts and uniform phantom diameter was studied numerically, determining the relative contribution of counts from lines of response passing through the phantom as compared with the total number of counts. Finally, the relation between patient weight and transmission scan duration was determined for 35 patients, who were scanned at the level of thorax or pelvis. After installation of new rod sources, the NEC of transmission scans first increased slightly (5%) with decreasing rod source activity and after 3 months decreased with a rate of 2-3% per month. The numerical simulation showed that the number of transmission scan counts from lines of response passing through the phantom increased with phantom diameter up to 7 cm. For phantoms larger than 7 cm, the number of these counts decreased at approximately the same rate as the total number of transmission scan counts. Patient data confirmed that the total number of transmission scan counts decreased with increasing patient weight with about 0.5% kg(-1). It can be concluded that count-based transmission scans compensate for radioactive decay of the rod sources. With count-based transmission scans, rod sources can be used for up to 1.5 years at the cost of a 50% increased transmission scan duration. For phantoms with diameters of more than 7 cm and for patients scanned at the level of thorax or pelvis, use of count-based

  1. NOTE: Optimization of attenuation correction for positron emission tomography studies of thorax and pelvis using count-based transmission scans

    NASA Astrophysics Data System (ADS)

    Boellaard, R.; van Lingen, A.; van Balen, S. C. M.; Lammertsma, A. A.

    2004-02-01

    The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image quality and more precise quantification than with fixed transmission scan duration. First, the relation between noise equivalent counts (NEC) of 10 min calibration transmission scans and rod source activity was determined over a period of 1.5 years. Second, the relation between transmission scan counts and uniform phantom diameter was studied numerically, determining the relative contribution of counts from lines of response passing through the phantom as compared with the total number of counts. Finally, the relation between patient weight and transmission scan duration was determined for 35 patients, who were scanned at the level of thorax or pelvis. After installation of new rod sources, the NEC of transmission scans first increased slightly (5%) with decreasing rod source activity and after 3 months decreased with a rate of 2 3% per month. The numerical simulation showed that the number of transmission scan counts from lines of response passing through the phantom increased with phantom diameter up to 7 cm. For phantoms larger than 7 cm, the number of these counts decreased at approximately the same rate as the total number of transmission scan counts. Patient data confirmed that the total number of transmission scan counts decreased with increasing patient weight with about 0.5% kg-1. It can be concluded that count-based transmission scans compensate for radioactive decay of the rod sources. With count-based transmission scans, rod sources can be used for up to 1.5 years at the cost of a 50% increased transmission scan duration. For phantoms with diameters of more than 7 cm and for patients scanned at the level of thorax or pelvis, use of count-based

  2. Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror.

    PubMed

    Zhang, Hao; Xu, Dacheng; Zhang, Xiaoyang; Chen, Qiao; Xie, Huikai; Li, Suiqiong

    2015-12-10

    In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system.

  3. Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror

    PubMed Central

    Zhang, Hao; Xu, Dacheng; Zhang, Xiaoyang; Chen, Qiao; Xie, Huikai; Li, Suiqiong

    2015-01-01

    In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system. PMID:26690432

  4. Space-based infrared scanning sensor LOS determination and calibration using star observation

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Xu, Zhan; An, Wei; Deng, Xin-Pu; Yang, Jun-Gang

    2015-10-01

    This paper provides a novel methodology for removing sensor bias from a space based infrared (IR) system (SBIRS) through the use of stars detected in the background field of the sensor. Space based IR system uses the LOS (line of sight) of target for target location. LOS determination and calibration is the key precondition of accurate location and tracking of targets in Space based IR system and the LOS calibration of scanning sensor is one of the difficulties. The subsequent changes of sensor bias are not been taking into account in the conventional LOS determination and calibration process. Based on the analysis of the imaging process of scanning sensor, a theoretical model based on the estimation of bias angles using star observation is proposed. By establishing the process model of the bias angles and the observation model of stars, using an extended Kalman filter (EKF) to estimate the bias angles, and then calibrating the sensor LOS. Time domain simulations results indicate that the proposed method has a high precision and smooth performance for sensor LOS determination and calibration. The timeliness and precision of target tracking process in the space based infrared (IR) tracking system could be met with the proposed algorithm.

  5. Automated measurement of parameters related to the deformities of lower limbs based on x-rays images.

    PubMed

    Wojciechowski, Wadim; Molka, Adrian; Tabor, Zbisław

    2016-03-01

    Measurement of the deformation of the lower limbs in the current standard full-limb X-rays images presents significant challenges to radiologists and orthopedists. The precision of these measurements is deteriorated because of inexact positioning of the leg during image acquisition, problems with selecting reliable anatomical landmarks in projective X-ray images, and inevitable errors of manual measurements. The influence of the random errors resulting from the last two factors on the precision of the measurement can be reduced if an automated measurement method is used instead of a manual one. In the paper a framework for an automated measurement of various metric and angular quantities used in the description of the lower extremity deformation in full-limb frontal X-ray images is described. The results of automated measurements are compared with manual measurements. These results demonstrate that an automated method can be a valuable alternative to the manual measurements.

  6. Mode-dependent templates and scan order for H.264/AVC-based intra lossless coding.

    PubMed

    Gu, Zhouye; Lin, Weisi; Lee, Bu-Sung; Lau, Chiew Tong; Sun, Ming-Ting

    2012-09-01

    In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.

  7. An EST-based genome scan using 454 sequencing in the marine snail Littorina saxatilis.

    PubMed

    Galindo, J; Grahame, J W; Butlin, R K

    2010-09-01

    Genome scans have been used in the studies of ecological speciation to find genomic regions ('outlier loci') showing reduced gene flow between divergent populations/species. High-throughput sequencing ('454') offers new opportunities in this field via transcriptome sequencing. Divergent ecotypes of the marine gastropod Littorina saxatilis represent a good example of incipient ecological speciation. We performed a 454-based genome scan between H and M ecotypes of L. saxatilis from the British Isles using cDNA of pooled individuals. Allele frequencies were calculated for 2454 single nucleotide polymorphisms (SNPs), within 572 contigs, and 7% of loci were detected as outliers. Functional annotation of the contigs containing outlier SNPs showed that they included shell matrix and muscle proteins (lithostathine, mucin, titin), proteins involved in energetic metabolism (arginine kinase, NADH dehydrogenase) and reverse transcriptases. Follow-up investigations into these proteins and unannotated outliers will be a promising route in the study of ecological speciation in L. saxatilis.

  8. Wide-aperture, line-focused ultrasonic material characterization system based on lateral scanning.

    PubMed

    Titov, Sergey; Maev, Roman; Bogatchenkov, Alexey

    2003-08-01

    We present a new wide-aperture, line-focused ultrasonic material characterization system. The foci of the transmitting and receiving transducers are located in the specimen-immersion liquid interface; and the output voltage V(x,t) of the system is recorded as a function of the lateral position of the receiving transducer. The two-dimensional spectrum of V(x, t) can be expressed as a product of the transfer function of the system and the reflectance function of the interface. In comparison with a system based on scanning in the z direction, the angular resolution of the proposed technique increases with decreasing angle of incidence. There are no geometrical restrictions on the length of the recorded spatial data and the angle of incidence in the case of lateral scanning. The temperature coefficient of the measurement error is low because of the constancy of the propagation distance of ultrasound in the immersion fluid during data acquisition.

  9. Correlation-based technique for automated tunable diode laser scan stabilization

    NASA Technical Reports Server (NTRS)

    May, Randy D.

    1992-01-01

    A software-based method for real-time, active stabilization of tunable diode laser spectral scans is described. The procedure is suitable for use with field and laboratory instrumentation where automated, unattended spectrometer operation is required. An autocorrelation of two high-resolution reference gas infrared spectra is computed at regular intervals, and the location of the maximum value of the autocorrelation provides the relative abscissa shift between the spectra. Small adjustments to the laser scan parameters are thereby made to ensure that drifts in the laser output frequency are tracked and compensated. Calculations required for stabilization of a 512-point spectrum can be completed in under 25 ms using an inexpensive, moderate-speed, array processor installed in a PC.

  10. An entropy-based filtering approach for airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Zeng, Zhe; Wan, Jiaxin; Liu, Hui

    2016-03-01

    Parameter-tuning is a challenging task when generating digital terrain models from airborne laser scanning (light detection and ranging, LiDAR) data. To address this issue, this paper presents a filtering method for near-infrared laser scanning data that exploits the principle of entropy maximization as the optimization objective. The proposed approach generates ground elevation of point cloud by constructing a triangulated irregular network, calculates the entropy of the elevation from different parts, and automatically separates ground and non-ground points by the principle of entropy maximization. Experimental results from different ground surfaces show that the proposed entropy-based filtering method can effectively extract bare-earth points from the point cloud without adjusting thresholds.

  11. Volumetric display system based on three-dimensional scanning of inclined optical image.

    PubMed

    Miyazaki, Daisuke; Shiba, Kensuke; Sotsuka, Koji; Matsushita, Kenji

    2006-12-25

    A volumetric display system based on three-dimensional (3D) scanning of an inclined image is reported. An optical image of a two-dimensional (2D) display, which is a vector-scan display monitor placed obliquely in an optical imaging system, is moved laterally by a galvanometric mirror scanner. Inclined cross-sectional images of a 3D object are displayed on the 2D display in accordance with the position of the image plane to form a 3D image. Three-dimensional images formed by this display system satisfy all the criteria for stereoscopic vision because they are real images formed in a 3D space. Experimental results of volumetric imaging from computed-tomography images and 3D animated images are presented.

  12. Experimental demonstration of noninvasive transskull adaptive focusing based on prior computed tomography scans

    NASA Astrophysics Data System (ADS)

    Aubry, J.-F.; Tanter, M.; Pernot, M.; Thomas, J.-L.; Fink, M.

    2003-01-01

    Developing minimally invasive brain surgery by high-intensity focused ultrasound beams is of great interest in cancer therapy. However, the skull induces strong aberrations both in phase and amplitude, resulting in a severe degradation of the beam shape. Thus, an efficient brain tumor therapy would require an adaptive focusing, taking into account the effects of the skull. In this paper, we will show that the acoustic properties of the skull can be deduced from high resolution CT scans and used to achieve a noninvasive adaptive focusing. Simulations have been performed with a full 3-D finite differences code, taking into account all the heterogeneities inside the skull. The set of signals to be emitted in order to focus through the skull can thus be computed. The complete adaptive focusing procedure based on prior CT scans has been experimentally validated. This could have promising applications in brain tumor hyperthermia but also in transcranial ultrasonic imaging.

  13. Robust real-time mine classification based on side-scan sonar imagery

    NASA Astrophysics Data System (ADS)

    Bello, Martin G.

    2000-08-01

    We describe here image processing and neural network based algorithms for detection and classification of mines in side-scan sonar imagery, and the results obtained from their application to two distinct image data bases. These algorithms evolved over a period from 1994 to the present, originally at Draper Laboratory, and currently at Alphatech Inc. The mine-detection/classification system is partitioned into an anomaly screening stage followed by a classification stage involving the calculation of features on blobs, and their input into a multilayer perceptron neural network. Particular attention is given to the selection of algorithm parameters, and training data, in order to optimize performance over the aggregate data set.

  14. Asymmetric actuating structure generates negligible influence on the supporting base for high performance scanning probe microscopies

    NASA Astrophysics Data System (ADS)

    Yi Yan, Gang; Bin Liu, Yong; Hua Feng, Zhi

    2014-02-01

    An asymmetric actuating structure generating negligible influence on the supporting base for high performance scanning probe microscopies is proposed in this paper. The actuator structure consists of two piezostacks, one is used for actuating while the other is for counterbalancing. In contrast with balanced structure, the two piezostacks are installed at the same side of the supporting base. The effectiveness of the structure is proved by some experiments with the actuators fixed to the free end of a cantilever. Experimental results show that almost all of the vibration modes of the cantilever are suppressed effectively at a wide frequency range of 90 Hz-10 kHz.

  15. 3-D micro surface profilometry employing novel Mirau-based lateral scanning interferometry

    NASA Astrophysics Data System (ADS)

    Chen, Liang-Chia; Le, Manh-Trung; Lin, Yi-Shiuan

    2014-09-01

    An innovative 3-D surface imaging methodology for reconstructing micro surface profiles with a long depth measuring range and a nano-scale resolution was developed using the newly developed Mirau-based lateral scanning interferometry (LSI). The current measuring field of view (FOV) of conventional white light interferometers is limited by microscopic views of the existing interferometric objectives, such as those in Michelson, Mirau or Linnik designs. Moreover, the vertical scanning operation required for acquiring volumetric interferometric data is extremely time-consuming and makes white light vertical scanning interferometry (VSI) infeasible for automatic optical inspection (AOI) of micro 3-D structures. To resolve this, a newly developed white light LSI method based on Mirau’s optical configuration was developed by controlling the tilting angle of the reference mirror in the Mirau interferometric objective. With the proposed optical configuration, the surface is inspected at a tilting angle with respect to the maximum coherence plane of the interferometric system along its lateral scanning direction when the objective lies perpendicular to the tested surface. In addition, a system calibration method was developed to establish an accurate mathematical mapping model between the object depth and the lateral axis. To evaluate the feasibility of the methodology, a calibrated step height was measured for evaluating the accuracy and repeatability. Some industrial samples, such as photon spacers and other microstructures fabricated by nano-imprinting processes, were measured to verify the actual performance on real components. It was found that the measurement repeatability was controlled less than 60 nm within one standard deviation for a maximum measurable depth of 27.21 µm.

  16. Integrated vision-based robotic arm interface for operators with upper limb mobility impairments.

    PubMed

    Jiang, Hairong; Wachs, Juan P; Duerstock, Bradley S

    2013-06-01

    An integrated, computer vision-based system was developed to operate a commercial wheelchair-mounted robotic manipulator (WMRM). In this paper, a gesture recognition interface system developed specifically for individuals with upper-level spinal cord injuries (SCIs) was combined with object tracking and face recognition systems to be an efficient, hands-free WMRM controller. In this test system, two Kinect cameras were used synergistically to perform a variety of simple object retrieval tasks. One camera was used to interpret the hand gestures to send as commands to control the WMRM and locate the operator's face for object positioning. The other sensor was used to automatically recognize different daily living objects for test subjects to select. The gesture recognition interface incorporated hand detection, tracking and recognition algorithms to obtain a high recognition accuracy of 97.5% for an eight-gesture lexicon. An object recognition module employing Speeded Up Robust Features (SURF) algorithm was performed and recognition results were sent as a command for "coarse positioning" of the robotic arm near the selected daily living object. Automatic face detection was also provided as a shortcut for the subjects to position the objects to the face by using a WMRM. Completion time tasks were conducted to compare manual (gestures only) and semi-manual (gestures, automatic face detection and object recognition) WMRM control modes. The use of automatic face and object detection significantly increased the completion times for retrieving a variety of daily living objects.

  17. Skeletal limb abnormalities

    MedlinePlus

    ... medlineplus.gov/ency/article/003170.htm Skeletal limb abnormalities To use the sharing features on this page, please enable JavaScript. Skeletal limb abnormalities refers to a variety of bone structure problems ...

  18. Critical Limb Ischemia (CLI)

    MedlinePlus

    ... High blood pressure Family history of vascular disease Warning Signs You may have critical limb ischemia if ... blood flow to the limb. Other treatments include laser atherectomy, where small bits of plaque are vaporized ...

  19. Upper limb function and activity in people with facioscapulohumeral muscular dystrophy: a web-based survey.

    PubMed

    Bergsma, Arjen; Cup, Edith H C; Janssen, Mariska M H P; Geurts, Alexander C H; de Groot, Imelda J M

    2017-02-01

    Purpose To investigate the upper extremity (UE) at the level of impairments and related activity limitations and participation restrictions in people with facioscapulohumeral muscular dystrophy (FSHD). Methods The study was conducted using web-based questionnaires that were distributed amongst people with FSHD in the Netherlands. Eighty-eight respondents started the survey, and 71 completed it. The questionnaires covered the following dimensions: Function, Activity and Participation of the International Classification of Functioning Disability and Health. Results More than 40% of the respondents experienced pain in one arm or both the arms. Increased pain and stiffness scores and longer disease duration were associated with increased limitation scores. For basic activities, lifting the arm above shoulder-level was most frequently reported as most limited, coherent with the clinical picture of FSHD. Among the respondents, 50% indicated restrictions at school, 78% indicated restrictions at work and more than 80% indicated restrictions whilst participating in sports, hobbies, household activities and romantic relationships. Conclusions This study has shown that alongside the well-known problem of lifting the arms above shoulder-level, UE activities below shoulder height during vocational and occupational activities are also problematic in patients with FSHD. Alongside disease duration, pain and stiffness are associated with UE activity limitations. Implications for Rehabilitation Attention is needed for pain and experienced stiffness in the upper extremity as it is frequently present in patients with FSHD. Rehabilitation professionals need to be aware that patients with FSHD not only experience problems with activities above shoulder height, but also with activities below shoulder height. At least 50% of the patients with FSHD experience restrictions in participation as a result of limitations in their UE.

  20. Lipotyphla limb myology comparison.

    PubMed

    Neveu, Pauline; Gasc, Jean-Pierre

    2002-05-01

    Fore- and hindlimb muscles were dissected in four species of Lipotyphla: the western European hedgehog Erinaceus europaeus (Erinaceidae, Erinaceinae); the moonrat Echinosorex gymnura (Erinaceidae, Hylomyinae or Galericinae); the tailless tenrec Tenrec ecaudatus (Tenrecidae, Tenrecinae); and the common European white-toothed shrew Crocidura russula (Soricidae, Soricinae). This work completely reviews the limb musculature of these walking mammals. Twelve myological characters were evaluated in order to disclose phylogenetic relationships. The cladogram obtained supported previous ones based on cranial and dental characters. This study shows that myological characters are valuable in phylogenetic analyses.

  1. Scan Line Based Road Marking Extraction from Mobile LiDAR Point Clouds†

    PubMed Central

    Yan, Li; Liu, Hua; Tan, Junxiang; Li, Zan; Xie, Hong; Chen, Changjun

    2016-01-01

    Mobile Mapping Technology (MMT) is one of the most important 3D spatial data acquisition technologies. The state-of-the-art mobile mapping systems, equipped with laser scanners and named Mobile LiDAR Scanning (MLS) systems, have been widely used in a variety of areas, especially in road mapping and road inventory. With the commercialization of Advanced Driving Assistance Systems (ADASs) and self-driving technology, there will be a great demand for lane-level detailed 3D maps, and MLS is the most promising technology to generate such lane-level detailed 3D maps. Road markings and road edges are necessary information in creating such lane-level detailed 3D maps. This paper proposes a scan line based method to extract road markings from mobile LiDAR point clouds in three steps: (1) preprocessing; (2) road points extraction; (3) road markings extraction and refinement. In preprocessing step, the isolated LiDAR points in the air are removed from the LiDAR point clouds and the point clouds are organized into scan lines. In the road points extraction step, seed road points are first extracted by Height Difference (HD) between trajectory data and road surface, then full road points are extracted from the point clouds by moving least squares line fitting. In the road markings extraction and refinement step, the intensity values of road points in a scan line are first smoothed by a dynamic window median filter to suppress intensity noises, then road markings are extracted by Edge Detection and Edge Constraint (EDEC) method, and the Fake Road Marking Points (FRMPs) are eliminated from the detected road markings by segment and dimensionality feature-based refinement. The performance of the proposed method is evaluated by three data samples and the experiment results indicate that road points are well extracted from MLS data and road markings are well extracted from road points by the applied method. A quantitative study shows that the proposed method achieves an average

  2. Scan Line Based Road Marking Extraction from Mobile LiDAR Point Clouds.

    PubMed

    Yan, Li; Liu, Hua; Tan, Junxiang; Li, Zan; Xie, Hong; Chen, Changjun

    2016-06-17

    Mobile Mapping Technology (MMT) is one of the most important 3D spatial data acquisition technologies. The state-of-the-art mobile mapping systems, equipped with laser scanners and named Mobile LiDAR Scanning (MLS) systems, have been widely used in a variety of areas, especially in road mapping and road inventory. With the commercialization of Advanced Driving Assistance Systems (ADASs) and self-driving technology, there will be a great demand for lane-level detailed 3D maps, and MLS is the most promising technology to generate such lane-level detailed 3D maps. Road markings and road edges are necessary information in creating such lane-level detailed 3D maps. This paper proposes a scan line based method to extract road markings from mobile LiDAR point clouds in three steps: (1) preprocessing; (2) road points extraction; (3) road markings extraction and refinement. In preprocessing step, the isolated LiDAR points in the air are removed from the LiDAR point clouds and the point clouds are organized into scan lines. In the road points extraction step, seed road points are first extracted by Height Difference (HD) between trajectory data and road surface, then full road points are extracted from the point clouds by moving least squares line fitting. In the road markings extraction and refinement step, the intensity values of road points in a scan line are first smoothed by a dynamic window median filter to suppress intensity noises, then road markings are extracted by Edge Detection and Edge Constraint (EDEC) method, and the Fake Road Marking Points (FRMPs) are eliminated from the detected road markings by segment and dimensionality feature-based refinement. The performance of the proposed method is evaluated by three data samples and the experiment results indicate that road points are well extracted from MLS data and road markings are well extracted from road points by the applied method. A quantitative study shows that the proposed method achieves an average

  3. A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

    NASA Astrophysics Data System (ADS)

    Livesey, N. J.; Santee, M. L.; Manney, G. L.

    2015-04-01

    The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same airmass has been observed on multiple occasions. The method was pioneered using ozone sonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian Trajectory Diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an airmass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change on these timescales is negligible, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature. As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric

  4. The design and simulation of single detector MIR spectrometer based on MEMS scanning mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Zhong-wei; Wen, Zhi-yu; Zeng, Tian-ling; Wei, Kang-lin

    2011-08-01

    Infrared (IR) spectrometers are very important optical equipments that can be used in industry, science, medicine, agriculture, biology and food safety etc., and the market is growing. However, most traditional IR spectrometers, such as Fourier transform spectrometer (FTS) that based on Michelson interferometer principle and scanning monochromator that based on grating scanning, are expensive, relative large volume, and stationary, which can't meet the requirements of specific application such as rapidity, special environment and some special samples. To overcome these drawbacks, innovatory technology-micro electro mechanical systems (MEMS) technology was used in micro IR spectrometers in the past few years. And several prototypes and products that based on several operational principles have been emerged. In this paper, a novel IR micro spectrometer which based on MEMS technology and used single element detector was presented over a wide spectral range (from 2500nm to 5000nm) in the mid infrared (MIR) wavelength regime, and the optical system of it was designed on the basis of traditional scanning monochromator principle. In the optical system, there is a highlighted characteristic that dual spherical focus mirror was used to focus the diffraction light of the diffraction grating, which improved the spectral resolution of the optical system. Finally, using Zemax optical software, three torsion angle locations were selected to simulate the optical system of the spectrometer with the slit's size 0.1mm×1mm. The simulation result indicated that in the whole wavelength range the spectral resolution of the optical system was less than 30nm, and a high accuracy MIR spectrometer with compact volume will be realized in future hopefully.

  5. Omni-Directional Scanning Localization Method of a Mobile Robot Based on Ultrasonic Sensors.

    PubMed

    Mu, Wei-Yi; Zhang, Guang-Peng; Huang, Yu-Mei; Yang, Xin-Gang; Liu, Hong-Yan; Yan, Wen

    2016-12-20

    Improved ranging accuracy is obtained by the development of a novel ultrasonic sensor ranging algorithm, unlike the conventional ranging algorithm, which considers the divergence angle and the incidence angle of the ultrasonic sensor synchronously. An ultrasonic sensor scanning method is developed based on this algorithm for the recognition of an inclined plate and to obtain the localization of the ultrasonic sensor relative to the inclined plate reference frame. The ultrasonic sensor scanning method is then leveraged for the omni-directional localization of a mobile robot, where the ultrasonic sensors are installed on a mobile robot and follow the spin of the robot, the inclined plate is recognized and the position and posture of the robot are acquired with respect to the coordinate system of the inclined plate, realizing the localization of the robot. Finally, the localization method is implemented into an omni-directional scanning localization experiment with the independently researched and developed mobile robot. Localization accuracies of up to ±3.33 mm for the front, up to ±6.21 for the lateral and up to ±0.20° for the posture are obtained, verifying the correctness and effectiveness of the proposed localization method.

  6. Advances in Scanning Reflectarray Antennas Based on Ferroelectric Thin Film Phase Shifters for Deep Space Communications

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2007-01-01

    Though there are a few examples of scanning phased array antennas that have flown successfully in space, the quest for low-cost, high-efficiency, large aperture microwave phased arrays continues. Fixed and mobile applications that may be part of a heterogeneous exploration communication architecture will benefit from the agile (rapid) beam steering and graceful degradation afforded by phased array antennas. The reflectarray promises greater efficiency and economy compared to directly-radiating varieties. Implementing a practical scanning version has proven elusive. The ferroelectric reflectarray, under development and described herein, involves phase shifters based on coupled microstrip patterned on Ba(x)Sr(1-x)TiO3 films, that were laser ablated onto LaAlO3 substrates. These devices outperform their semiconductor counterparts from X- through and K-band frequencies. There are special issues associated with the implementation of a scanning reflectarray antenna, especially one realized with thin film ferroelectric phase shifters. This paper will discuss these issues which include: relevance of phase shifter loss; modulo 2(pi) effects and phase shifter transient effects on bit error rate; scattering from the ground plane; presentation of a novel hybrid ferroelectric-semiconductor phase shifter; and the effect of mild radiation exposure on phase shifter performance.

  7. Omni-Directional Scanning Localization Method of a Mobile Robot Based on Ultrasonic Sensors

    PubMed Central

    Mu, Wei-Yi; Zhang, Guang-Peng; Huang, Yu-Mei; Yang, Xin-Gang; Liu, Hong-Yan; Yan, Wen

    2016-01-01

    Improved ranging accuracy is obtained by the development of a novel ultrasonic sensor ranging algorithm, unlike the conventional ranging algorithm, which considers the divergence angle and the incidence angle of the ultrasonic sensor synchronously. An ultrasonic sensor scanning method is developed based on this algorithm for the recognition of an inclined plate and to obtain the localization of the ultrasonic sensor relative to the inclined plate reference frame. The ultrasonic sensor scanning method is then leveraged for the omni-directional localization of a mobile robot, where the ultrasonic sensors are installed on a mobile robot and follow the spin of the robot, the inclined plate is recognized and the position and posture of the robot are acquired with respect to the coordinate system of the inclined plate, realizing the localization of the robot. Finally, the localization method is implemented into an omni-directional scanning localization experiment with the independently researched and developed mobile robot. Localization accuracies of up to ±3.33 mm for the front, up to ±6.21 for the lateral and up to ±0.20° for the posture are obtained, verifying the correctness and effectiveness of the proposed localization method. PMID:27999396

  8. Three-dimensional measurement of multilayer thin films based on scanning white light interferometer

    NASA Astrophysics Data System (ADS)

    Shi, Zhendong; Zhang, Lin; Ren, Huan; Yuan, Quan; Yang, Yi; Ma, Hua

    2016-09-01

    For multilayer films system, in order to obtain the thickness and surface profile in each layer of thin film, a method to measure the 3D morphology of a multilayer films system based on scanning white light interferometer has been proposed in this article. At first, the mathematical relationship between reflection phase and thickness of each film layer has been obtained by using the electromagnetic field boundary conditions. Then, a nonlinear least square algorithm has been used to fit the reflection phase which had been found through a scanning white light interferometer, in this way the linear and nonlinear terms of the reflection phase have been separated, which made it possible to measure top-layer surface profile and thickness of each thin film layer respectively and avoided the interference with each other, because the linear term is related to the top layer's surface profile but the nonlinear term is correlated to the thickness of each film layer in multilayer thin films system. Thus, the three-dimensional morphology of multilayer thin films system could be reconstructed. Experimental results showed this method was effective in the three-dimensional morphology measurement for multilayer thin films. And the measurement could be completed just using the existing commercial scanning white light interferometer, as a consequence the measurement cost is low, and the operation will be quite simple.

  9. Quantitative analysis of multiple components based on liquid chromatography with mass spectrometry in full scan mode.

    PubMed

    Xu, Min Li; Li, Bao Qiong; Wang, Xue; Chen, Jing; Zhai, Hong Lin

    2016-08-01

    Although liquid chromatography with mass spectrometry in full scan mode can obtain all the signals simultaneously in a large range and low cost, it is rarely used in quantitative analysis due to several problems such as chromatographic drifts and peak overlap. In this paper, we propose a Tchebichef moment method for the simultaneous quantitative analysis of three active compounds in Qingrejiedu oral liquid based on three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry. After the Tchebichef moments were calculated directly from the spectra, the quantitative linear models for three active compounds were established by stepwise regression. All the correlation coefficients were more than 0.9978. The limits of detection and limits of quantitation were less than 0.11 and 0.49 μg/mL, respectively. The intra- and interday precisions were less than 6.54 and 9.47%, while the recovery ranged from 102.56 to 112.15%. Owing to the advantages of multi-resolution and inherent invariance properties, Tchebichef moments could provide favorable results even in the situation of peaks shifting and overlapping, unknown interferences and noise signals, so it could be applied to the analysis of three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry.

  10. A Horn-fed Frequency Scanning Holographic Antenna Based on Generalized Law of Reflection

    PubMed Central

    Liu, Dawei; Cheng, Bo; Pan, Xiaotian; Qiao, Lifang

    2016-01-01

    A new method of designing horn-fed frequency scanning holographic antenna is proposed. The artificial surface design of holographic antenna is based on generalized law of reflection. The input admittance is utilized to construct the interference pattern of the surface which is intervened by the excitation wave and the required radiation wave. The scalar admittance unit cell which is composed of sub-wavelength metallic patch on grounded dielectric substrate is implemented to design artificial surface, and the simulation results are just as expected that the antenna can scan the beam as the frequency changes. Furthermore, a cross shaped patch printed on grounded dielectric unit cells is used to reduce the designing complexity of tensor admittance surface. At last, a frequency scanning holographic antenna with tensor admittance surface with ability of changing linear polarization excitation wave to left-hand circular polarization (LCP) radiation wave is designed and fabricated. The full-wave simulation and experimental results show well agreement and confirm the method proposed. PMID:27515782

  11. Display MTF measurements based on scanning and imaging technologies and its importance in the application space

    NASA Astrophysics Data System (ADS)

    Kaur, Balvinder; Olson, Jeff; Flug, Eric A.

    2016-05-01

    Measuring the Modulation Transfer Function (MTF) of a display monitor is necessary for many applications such as: modeling end-to-end systems, conducting perception experiments, and performing targeting tasks in real-word scenarios. The MTF of a display defines the resolution properties and quantifies how well the spatial frequencies are displayed on a monitor. Many researchers have developed methods to measure display MTFs using either scanning or imaging devices. In this paper, we first present methods to measure display MTFs using two separate technologies and then discuss the impact of a display MTF on a system's performance. The two measurement technologies were scanning with a photometer and imaging with a CMOS based camera. To estimate a true display MTF, measurements made with the photometer were backed out for the scanning optics aperture. The developed methods were applied to measure MTFs of the two types of monitors, Cathode Ray Tube (CRT) and Liquid Crystal Display (LCD). The accuracy of the measured MTFs was validated by comparing MTFs measured with the two systems. The methods presented here are simple and can be easily implemented employing either a Prichard photometer or an imaging device. In addition, the impact of a display MTF on the end-to-end performance of a system was modeled using NV-IPM.

  12. Health Literacy Environmental Scans of Community-Based Dental Clinics in Maryland

    PubMed Central

    Maybury, Catherine; Kleinman, Dushanka V.; Radice, Sarah D.; Wang, Min Qi; Child, Wendy; Rudd, Rima E.

    2014-01-01

    Objectives. We conducted health literacy environmental scans in 26 Maryland community-based dental clinics to identify institutional characteristics and provider practices that affect dental services access and dental caries education. Methods. In 2011–2012 we assessed user friendliness of the clinics including accessibility, signage, facility navigation, educational materials, and patient forms. We interviewed patients and surveyed dental providers about their knowledge and use of communication techniques. Results. Of 32 clinics, 26 participated. Implementation of the health literacy environmental scan tools was acceptable to the dental directors and provided clinic directors with information to enhance care and outreach. We found considerable variation among clinic facilities, operations, and content of educational materials. There was less variation in types of insurance accepted, no-show rates, methods of communicating with patients, and electronic health records use. Providers who had taken a communication skills course were more likely than those who had not to use recommended communication techniques. Conclusions. Our findings provide insight into the use of health literacy environmental scan tools to identify clinic and provider characteristics and practices that can be used to make dental environments more user friendly and health literate. PMID:24922128

  13. Bypassing of stems versus linear base-by-base inspection of mammalian mRNAs during ribosomal scanning.

    PubMed

    Abaeva, Irina S; Marintchev, Assen; Pisareva, Vera P; Hellen, Christopher U T; Pestova, Tatyana V

    2011-01-05

    Initiation codon selection in eukaryotes involves base-by-base inspection of the 5'-untranslated region of mRNA by scanning ribosomal 43S preinitiation complexes. We employed in vitro reconstitution to investigate factor requirements for this process and report that in the absence of eIF1 and DHX29, eIFs 4A, 4B and 4G promote efficient bypassing of stable stems by scanning 43S complexes and formation of 48S initiation complexes on AUG codons immediately upstream and downstream of such stems, without their unwinding. However, intact stems are not threaded through the entire mRNA Exit channel of the 40S subunit, resulting in incorrect positioning of mRNA upstream of the ribosomal P site in 48S complexes formed on AUG codons following intact stems, which renders them susceptible to dissociation by eIF1. In 48S complexes formed on AUG codons preceding intact stems, the stems are accommodated in the A site. Such aberrant complexes are destabilized by DHX29, which also ensures that mRNA enters the mRNA-binding cleft in a single-stranded form and therefore undergoes base-by-base inspection during scanning.

  14. Determination of the smoke-plume heights and their dynamics with ground-based scanning lidar.

    PubMed

    Kovalev, V; Petkov, A; Wold, C; Urbanski, S; Hao, W M

    2015-03-10

    Lidar-data processing techniques are analyzed, which allow determining smoke-plume heights and their dynamics and can be helpful for the improvement of smoke dispersion and air quality models. The data processing algorithms considered in the paper are based on the analysis of two alternative characteristics related to the smoke dispersion process: the regularized intercept function, extracted directly from the recorded lidar signal, and the square-range corrected backscatter signal, obtained after determining and subtracting the constant offset in the recorded signal. The analysis is performed using experimental data of the scanning lidar obtained in the area of prescribed fires.

  15. Documenting Bronze Age Akrotiri on Thera Using Laser Scanning, Image-Based Modelling and Geophysical Prospection

    NASA Astrophysics Data System (ADS)

    Trinks, I.; Wallner, M.; Kucera, M.; Verhoeven, G.; Torrejón Valdelomar, J.; Löcker, K.; Nau, E.; Sevara, C.; Aldrian, L.; Neubauer, E.; Klein, M.

    2017-02-01

    The excavated architecture of the exceptional prehistoric site of Akrotiri on the Greek island of Thera/Santorini is endangered by gradual decay, damage due to accidents, and seismic shocks, being located on an active volcano in an earthquake-prone area. Therefore, in 2013 and 2014 a digital documentation project has been conducted with support of the National Geographic Society in order to generate a detailed digital model of Akrotiri's architecture using terrestrial laser scanning and image-based modeling. Additionally, non-invasive geophysical prospection has been tested in order to investigate its potential to explore and map yet buried archaeological remains. This article describes the project and the generated results.

  16. Miniaturized multimodal CARS microscope based on MEMS scanning and a single laser source.

    PubMed

    Murugkar, Sangeeta; Smith, Brett; Srivastava, Prateek; Moica, Adrian; Naji, Majid; Brideau, Craig; Stys, Peter K; Anis, Hanan

    2010-11-08

    We demonstrate a novel miniaturized multimodal coherent anti-Stokes Raman scattering (CARS) microscope based on microelectromechanical systems (MEMS) scanning mirrors and custom miniature optics. A single Ti:sapphire femtosecond pulsed laser is used as the light source to produce the CARS, two photon excitation fluorescence (TPEF) and second harmonic generation (SHG) images using this miniaturized microscope. The high resolution and distortion-free images obtained from various samples such as a USAF target, fluorescent and polystyrene microspheres and biological tissue successfully demonstrate proof of concept, and pave the path towards future integration of parts into a handheld multimodal CARS probe for non- or minimally-invasive in vivo imaging.

  17. [Hyperspectral acquisition system for tongue inspection based on X-Y scanning galvanometer].

    PubMed

    Li, Gang; Zhao, Jing; Lin, Ling; Zhang, Bao-ju

    2011-12-01

    Hyperspectral was used for tongue inspection in the present work to resolve the problem that information of current research for tongue inspection was inadequate. A hyperspectral acquisition system based on X-Y scanning galvanometer was also proposed due to the high cost of the current hyperspectral apparatus. An experiment was made to test the ability of this system. By collecting the hyperspectral information of color pictures with size similar to the tongue, the results of experiment showed that this system can acquire more information of tongue than other methods, and this method can provide a new way for tongue inspection.

  18. 4D offline PET-based treatment verification in scanned ion beam therapy: a phantom study

    NASA Astrophysics Data System (ADS)

    Kurz, Christopher; Bauer, Julia; Unholtz, Daniel; Richter, Daniel; Stützer, Kristin; Bert, Christoph; Parodi, Katia

    2015-08-01

    At the Heidelberg Ion-Beam Therapy Center, patient irradiation with scanned proton and carbon ion beams is verified by offline positron emission tomography (PET) imaging: the {β+} -activity measured within the patient is compared to a prediction calculated on the basis of the treatment planning data in order to identify potential delivery errors. Currently, this monitoring technique is limited to the treatment of static target structures. However, intra-fractional organ motion imposes considerable additional challenges to scanned ion beam radiotherapy. In this work, the feasibility and potential of time-resolved (4D) offline PET-based treatment verification with a commercial full-ring PET/CT (x-ray computed tomography) device are investigated for the first time, based on an experimental campaign with moving phantoms. Motion was monitored during the gated beam delivery as well as the subsequent PET acquisition and was taken into account in the corresponding 4D Monte-Carlo simulations and data evaluation. Under the given experimental conditions, millimeter agreement between the prediction and measurement was found. Dosimetric consequences due to the phantom motion could be reliably identified. The agreement between PET measurement and prediction in the presence of motion was found to be similar as in static reference measurements, thus demonstrating the potential of 4D PET-based treatment verification for future clinical applications.

  19. Preprocessing of A-scan GPR data based on energy features

    NASA Astrophysics Data System (ADS)

    Dogan, Mesut; Turhan-Sayan, Gonul

    2016-05-01

    There is an increasing demand for noninvasive real-time detection and classification of buried objects in various civil and military applications. The problem of detection and annihilation of landmines is particularly important due to strong safety concerns. The requirement for a fast real-time decision process is as important as the requirements for high detection rates and low false alarm rates. In this paper, we introduce and demonstrate a computationally simple, timeefficient, energy-based preprocessing approach that can be used in ground penetrating radar (GPR) applications to eliminate reflections from the air-ground boundary and to locate the buried objects, simultaneously, at one easy step. The instantaneous power signals, the total energy values and the cumulative energy curves are extracted from the A-scan GPR data. The cumulative energy curves, in particular, are shown to be useful to detect the presence and location of buried objects in a fast and simple way while preserving the spectral content of the original A-scan data for further steps of physics-based target classification. The proposed method is demonstrated using the GPR data collected at the facilities of IPA Defense, Ankara at outdoor test lanes. Cylindrically shaped plastic containers were buried in fine-medium sand to simulate buried landmines. These plastic containers were half-filled by ammonium nitrate including metal pins. Results of this pilot study are demonstrated to be highly promising to motivate further research for the use of energy-based preprocessing features in landmine detection problem.

  20. Artifact reduction in short-scan CBCT by use of optimization-based reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Zheng; Han, Xiao; Pearson, Erik; Pelizzari, Charles; Sidky, Emil Y.; Pan, Xiaochuan

    2016-05-01

    Increasing interest in optimization-based reconstruction in research on, and applications of, cone-beam computed tomography (CBCT) exists because it has been shown to have to potential to reduce artifacts observed in reconstructions obtained with the Feldkamp-Davis-Kress (FDK) algorithm (or its variants), which is used extensively for image reconstruction in current CBCT applications. In this work, we carried out a study on optimization-based reconstruction for possible reduction of artifacts in FDK reconstruction specifically from short-scan CBCT data. The investigation includes a set of optimization programs such as the image-total-variation (TV)-constrained data-divergency minimization, data-weighting matrices such as the Parker weighting matrix, and objects of practical interest for demonstrating and assessing the degree of artifact reduction. Results of investigative work reveal that appropriately designed optimization-based reconstruction, including the image-TV-constrained reconstruction, can reduce significant artifacts observed in FDK reconstruction in CBCT with a short-scan configuration.

  1. Design and test of a Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during training of upper limb movement.

    PubMed

    Simonsen, Daniel; Popovic, Mirjana B; Spaich, Erika G; Andersen, Ole Kæseler

    2017-03-25

    The present paper describes the design and test of a low-cost Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during the execution of an upper limb exercise. Eleven sub-acute stroke patients with varying degrees of upper limb function were recruited. Each subject participated in a control session (repeated twice) and a feedback session (repeated twice). In each session, the subjects were presented with a rectangular pattern displayed on a vertical mounted monitor embedded in the table in front of the patient. The subjects were asked to move a marker inside the rectangular pattern by using their most affected hand. During the feedback session, the thickness of the rectangular pattern was changed according to the performance of the subject, and the color of the marker changed according to its position, thereby guiding the subject's movements. In the control session, the thickness of the rectangular pattern and the color of the marker did not change. The results showed that the movement similarity and smoothness was higher in the feedback session than in the control session while the duration of the movement was longer. The present study showed that adaptive visual feedback delivered by use of the Kinect sensor can increase the similarity and smoothness of upper limb movement in stroke patients.

  2. The Special Sensor Ultraviolet Limb Imager instruments

    NASA Astrophysics Data System (ADS)

    Dymond, K. F.; Nicholas, A. C.; Budzien, S. A.; Coker, C.; Stephan, A. W.; Chua, D. H.

    2017-02-01

    The Special Sensor Ultraviolet Limb Imager (SSULI) instruments are ultraviolet limb scanning sensors flying on the United States Air Force Defense Meteorological Satellite Program Block 5D-3 satellites. The SSULIs cover the 800-1700 Å wavelength range at 18 Å spectral resolution. This wavelength range contains spectral signatures of all the dominant neutral and ionized species in the thermosphere and F region ionosphere. The instruments view ahead of the spacecraft and operate as limb imagers covering the 100-750 km altitude range at 10-15 km resolution with a 90 s scan cadence. We describe these instruments and summarize their calibration and on-orbit performance. Day-to-day variability of the nighttime ionosphere at low latitudes and longer-term variability of the global mean exospheric temperature are highlighted.

  3. 3D modelling of facade features on large sites acquired by vehicle based laser scanning

    NASA Astrophysics Data System (ADS)

    Boulaassal, H.; Landes, T.; Grussenmeyer, P.

    2011-12-01

    Mobile mapping laser scanning systems have become more and more widespread for the acquisition of millions of 3D points on large and geometrically complex urban sites. Vehicle-based Laser Scanning (VLS) systems travel many kilometers while acquiring raw point clouds which are registered in real time in a common coordinate system. Improvements of the acquisition steps as well as the automatic processing of the collected point clouds are still a conundrum for researchers. This paper shows some results obtained by application, on mobile laser scanner data, of segmentation and reconstruction algorithms intended initially to generate individual vector facade models using stationary Terrestrial Laser Scanner (TLS) data. The operating algorithms are adapted so as to take into account characteristics of VLS data. The intrinsic geometry of a point cloud as well as the relative geometry between registered point clouds are different from that obtained by a static TLS. The amount of data provided by this acquisition technique is another issue. Such particularities should be taken into consideration while processing this type of point clouds. The segmentation of VLS data is carried out based on an adaptation of RANSAC algorithm. Edge points of each element are extracted by applying a second algorithm. Afterwards, the vector models of each facade element are reconstructed. In order to validate the results, large samples with different characteristics have been introduced in the developed processing chain. The limitations as well as the capabilities of each process will be emphasized in terms of geometry and processing time.

  4. Triangular mesh establishment of 3D laser scanning data based on ellipsoidal projection

    NASA Astrophysics Data System (ADS)

    Zheng, De-hua; Xu, Jia; Li, Jia; Wang, Xin-sen

    2011-10-01

    The establishment of high quality triangular mesh is one of the key steps in 3D laser scanning data processing. Traditional triangulation algorithms have been proposed directly on the basis of adjacency relation between points in 3D space. However, when the point density is non-uniform or the noise exists, the problems such as surface hole, dough sheet overlapping and inconsistent normal appear easily. In this paper, a triangular mesh establishing algorithm based on ellipsoidal projection is proposed. After comparing the theory of ellipsoidal projection and cylindrical projection, the proposed triangular mesh establishing algorithm is analyzed in detail including basic idea and implementation method. To evaluate the performance and efficiency of the proposed algorithm, two experiments are then carried out on the 3D point cloud data of a foundation pit. The results indicate that though the computational efficiency of proposed algorithm is a little inferior to the algorithm based on cylindrical projection, the proposed algorithm is more effective for establishing point cloud of both top and bottom of the object and the original topological relation of 3D scanning points can be maintained better.

  5. Geometry and intensity based culvert detection in mobile laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Lin, Yi; Hyyppa, Juha

    2010-11-01

    Mobile laser scanning (MLS), which recently has been developing so quickly as a promising technology for mapping and remote sensing (RS), offers a good means to measure the fundamental geographic data, e.g. culverts, for urban planning and road engineering. This study as the first try presents a new automatic method to detect culverts in MLS point clouds, in which actually only partial characterization of this category of objects can be presented due to the restricted scanning zenith of MLS. The schematic is based on the raster-form of the data, and the digital terrain models (DTMs) with multi-leveled resolutions are first yielded by local minimum filtering. Then, the common layout of the expanded areas containing culverts is generalized as the theoretical basis, and the schematic components are derived to deploy the concrete judgment. The geometry and intensity information about culverts are both utilized to determine the real locations from coarse- to fine-scales. Numerical analysis based on the real-measured MLS data at the Espoonlahti test site has basically validated the proposed approach. Concretely, the statistical errors of the retrieved lengths and widths of the pedestrian culverts are less than 9% and 16% compared to the real ones individually, notwithstanding the inner heights innately in-accessible.

  6. A novel antibody humanization method based on epitopes scanning and molecular dynamics simulation.

    PubMed

    Zhang, Ding; Chen, Cai-Feng; Zhao, Bin-Bin; Gong, Lu-Lu; Jin, Wen-Jing; Liu, Jing-Jun; Wang, Jing-Fei; Wang, Tian-Tian; Yuan, Xiao-Hui; He, You-Wen

    2013-01-01

    1-17-2 is a rat anti-human DEC-205 monoclonal antibody that induces internalization and delivers antigen to dendritic cells (DCs). The potentially clinical application of this antibody is limited by its murine origin. Traditional humanization method such as complementarity determining regions (CDRs) graft often leads to a decreased or even lost affinity. Here we have developed a novel antibody humanization method based on computer modeling and bioinformatics analysis. First, we used homology modeling technology to build the precise model of Fab. A novel epitope scanning algorithm was designed to identify antigenic residues in the framework regions (FRs) that need to be mutated to human counterpart in the humanization process. Then virtual mutation and molecular dynamics (MD) simulation were used to assess the conformational impact imposed by all the mutations. By comparing the root-mean-square deviations (RMSDs) of CDRs, we found five key residues whose mutations would destroy the original conformation of CDRs. These residues need to be back-mutated to rescue the antibody binding affinity. Finally we constructed the antibodies in vitro and compared their binding affinity by flow cytometry and surface plasmon resonance (SPR) assay. The binding affinity of the refined humanized antibody was similar to that of the original rat antibody. Our results have established a novel method based on epitopes scanning and MD simulation for antibody humanization.

  7. Bilateral control-based compensation for rotation in imaging in scan imaging systems

    NASA Astrophysics Data System (ADS)

    Tian, Dapeng; Wang, Yutang; Wang, Fuchao; Zhang, Yupeng

    2015-12-01

    Scan imaging systems rely on the rotation of a mirror to scan an image. The rotation in the resulting image must be compensated to prevent information loss. Satisfactory performance of an imaging system is difficult to achieve when employing the methods of mechanical transmission and unilateral tracking control, especially when the system suffers from nonlinear factors, disturbances, and dynamic uncertainties. This paper proposes a compensation method based on bilateral control derived from the field of haptic robots. A two-loop disturbance observer was designed to guarantee that the dynamic characteristics of the motor are close to those of the nominal model. The controllers were designed on the basis of the small gain theorem. Experiments were conducted for a comparison with the traditional unilateral control-based compensation. The comparison showed a reduction of 99.83% in the L2 norm of error, which validates the method. The proposed method improves the accuracy of compensation for rotation in imaging, and demonstrates that bilateral control has feasibility for application in various fields, including photogrammetry.

  8. Photo-Based 3d Scanning VS. Laser Scanning - Competitive Data Acquisition Methods for Digital Terrain Modelling of Steep Mountain Slopes

    NASA Astrophysics Data System (ADS)

    Kolecka, N.

    2011-09-01

    The paper presents how terrestrial laser scanning (TLS) and terrestrial digital photogrammetry were used to create a 3D model of a steep mountain wall. Terrestrial methods of data acquisition are the most suitable for such relief, as the most effective registration is perpendicular to the surface. First, various aspects of photo-based scanning and laser scanning were discussed. The general overview of both technologies was followed by the description of a case study of the western wall of the Kościelec Mountain (2155 m). The case study area is one of the most interesting and popular rock climbing areas in the Polish High Tatra Mts. The wall is about 300 meters high, has varied relief and some parts are overhung. Triangular irregular mesh was chosen to represent the true- 3D surface with its complicated relief. To achieve a more smooth result for visualization NURBS curves and surfaces were utilized. Both 3D models were then compared to the standard DTM of the Tatra Mountains in TIN format, obtained from aerial photographs (0.2 m ground pixel size). The results showed that both TLS and terrestrial photogrammetry had similar accuracy and level of detail and could effectively supplement very high resolution DTMs of the mountain areas.

  9. A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

    NASA Astrophysics Data System (ADS)

    Livesey, N. J.; Santee, M. L.; Manney, G. L.

    2015-09-01

    The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same air mass has been observed on multiple occasions. The method was pioneered using ozonesonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian trajectory diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an air mass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change is negligible on the weekly to monthly timescales considered here, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature (~ 18 km altitude). As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This

  10. Highly Sensitive Electrical Detection of HIV-1 Virus Based on Scanning Tunneling Microscopy.

    PubMed

    Lee, Jin-Ho; Kim, Byung-Chan; Oh, Byung-Keun; Choi, Jeong-Woo

    2015-02-01

    A highly sensitive immunosensor based on scanning tunneling microscopy (STM) was developed for the first time to detect living material such as HIV-1 virus by gold (Au) nanoparticle and fragmented antibody complex. Fragmented antibodies were pre-immobilized on the Au surface, then HIV-1 virus like particles (HIV-1 VLPs) and Au-nanoparticle and fragmented antibody complexes were applied to develop sandwich assay. The developed surface morphology and the current profile of fabricated immunosensing element were characterized by Raman spectroscopy and investigated with STM. The power spectrum derived from the current profile was found to be related with concentrations of HIV-1 VLPs. Using the electrical detection method based on current mapping profile of STM, living material such as virus, HIV-1 VLPs, was able to be detected successfully. The proposed technique can be a promising method to construct the highly sensitive and efficient sensor for detecting viruses and other living materials.

  11. Hologram-based watermarking capable of surviving print-scan process.

    PubMed

    Wang, Shuozhong; Huang, Sujuan; Zhang, Xinpeng; Wu, Wei

    2010-03-01

    We propose a watermarking scheme for hardcopy pictures based on computer-generated holography. A hologram of the watermark is produced using a conjugate-symmetric extension technique, and its spectrum is inserted into the discrete cosine transform domain of the image. Adjusting the watermark placement in a data array, a trade-off between transparency and robustness is achieved. Anticropping and the interference-resisting capability of holograms make the watermark robust against manipulations commonly performed on digital images during postprocessing, including contrast enhancement, moderate smoothing and sharpening, and, in particular, geometric transformation. Most importantly, the proposed hologram-based watermarking can withstand the printing-scanning attack and, therefore, is useful in protecting copyright of digital photographs both as electronic and hardcopy versions.

  12. An efficient solid modeling system based on a hand-held 3D laser scan device

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Xu, Jun; Xu, Chenxi; Pan, Ming

    2014-12-01

    The hand-held 3D laser scanner sold in the market is appealing for its port and convenient to use, but price is expensive. To develop such a system based cheap devices using the same principles as the commercial systems is impossible. In this paper, a simple hand-held 3D laser scanner is developed based on a volume reconstruction method using cheap devices. Unlike convenient laser scanner to collect point cloud of an object surface, the proposed method only scan few key profile curves on the surface. Planar section curve network can be generated from these profile curves to construct a volume model of the object. The details of design are presented, and illustrated by the example of a complex shaped object.

  13. Comparison of Control Algorithms for a MEMS-based Adaptive Optics Scanning Laser Ophthalmoscope

    PubMed Central

    Li, Kaccie Y.; Mishra, Sandipan; Tiruveedhula, Pavan; Roorda, Austin

    2010-01-01

    We compared four algorithms for controlling a MEMS deformable mirror of an adaptive optics (AO) scanning laser ophthalmoscope. Interferometer measurements of the static nonlinear response of the deformable mirror were used to form an equivalent linear model of the AO system so that the classic integrator plus wavefront reconstructor type controller can be implemented. The algorithms differ only in the design of the wavefront reconstructor. The comparisons were made for two eyes (two individuals) via a series of imaging sessions. All four controllers performed similarly according to estimated residual wavefront error not reflecting the actual image quality observed. A metric based on mean image intensity did consistently reflect the qualitative observations of retinal image quality. Based on this metric, the controller most effective for suppressing the least significant modes of the deformable mirror performed the best. PMID:20454552

  14. Evaluation of scanning Maxwell-stress microscopy for SPM-based nanoelectronics

    NASA Astrophysics Data System (ADS)

    Dagata, J. A.

    1997-09-01

    A preliminary evaluation of the compatibility, spatial resolution, and sensitivity of scanning Maxwell-stress microscopy (SMM) as an in situ diagnostic technique for SPM oxidation of silicon is presented. These results indicate that SMM will provide us with a more detailed understanding of the reaction mechanism which occurs at the tip - sample junction during SPM oxidation. SMM also appears to be a promising technique for simultaneously investigating dimensional and electrical properties of molecular distributions within highly complex micro-environments such as phase-separated polymer systems. This effort to integrate SPM-based fabrication and diagnostics is discussed in terms of the development of predictive physical models for the optimization of the fabrication process and possible choices of future SPM-based nanodevices.

  15. Echo signal processing of laser rapid scanning based on wavelet transform

    NASA Astrophysics Data System (ADS)

    Chen, Jinling; Xu, Zhengfeng; Xie, Delin; Chen, Hongbin; Luo, Jian

    2007-12-01

    In order to get the edge message of a target, a laser scanning system was established. The laser scanning system steers a beam of laser energy which is dithered in two directions to scan the surface of the object. A laser energy detector detects laser energy reflected from the target. The reflected information is filtered to distinguish dither frequencies for signal in both directions. The signals are independently analyzed to determine the edge of the target by detecting the change of reflected laser energy. In order to get the fantastic point of echo signal, wavelet transform is used. Based on invariability of the quality factor of wavelet transform, combined with proper wavelet group, this paper discusses the application of wavelet transform for the detection of echo signal. On the basis of algorithm analysis, from aspects of detecting principle, detecting steps and computer emulation, the authors expatiate how to use wavelet transform to find the fantastic point of echo signal, finally to find the edge of the target being detected. Wavelet transform has the ability of denoting local signal characteristics, so it is fit to analyzing instantaneous and fantastic phenomena and can lay out signal components. The method in this paper will supply an algorithm gist and a reference for signal processing for the detection of edge message of target. The results are demonstrated by using Matlab programme. By the measure, the noise can be eliminated, and effective signals can be picked up. When applying the wavelet transform to experimentation, a satisfactory result was obtained. When using this method, the ability of edge detection can be greatly improved.

  16. Telescope beam-profile diagnostics and the solar limb

    NASA Technical Reports Server (NTRS)

    Lindsey, Charles A.; Roellig, Thomas L.

    1991-01-01

    The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation.

  17. Telescope beam-profile diagnostics and the solar limb

    SciTech Connect

    Lindsey, C.A.; Roellig, T.L. NASA, Ames Research Center, Moffett Field, CA )

    1991-07-01

    The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation. 16 refs.

  18. [The linear hyperspectral camera rotating scan imaging geometric correction based on the precise spectral sampling].

    PubMed

    Wang, Shu-min; Zhang, Ai-wu; Hu, Shao-xing; Wang, Jing-meng; Meng, Xian-gang; Duan, Yi-hao; Sun, Wei-dong

    2015-02-01

    As the rotation speed of ground based hyperspectral imaging system is too fast in the image collection process, which exceeds the speed limitation, there is data missed in the rectified image, it shows as the_black lines. At the same time, there is serious distortion in the collected raw images, which effects the feature information classification and identification. To solve these problems, in this paper, we introduce the each component of the ground based hyperspectral imaging system at first, and give the general process of data collection. The rotation speed is controlled in data collection process, according to the image cover area of each frame and the image collection speed of the ground based hyperspectral imaging system, And then the spatial orientation model is deduced in detail combining with the star scanning angle, stop scanning angle and the minimum distance between the sensor and the scanned object etc. The oriented image is divided into grids and resampled with new spectral. The general flow of distortion image corrected is presented in this paper. Since the image spatial resolution is different between the adjacent frames, and in order to keep the highest image resolution of corrected image, the minimum ground sampling distance is employed as the grid unit to divide the geo-referenced image. Taking the spectral distortion into account caused by direct sampling method when the new uniform grids and the old uneven grids are superimposed to take the pixel value, the precise spectral sampling method based on the position distribution is proposed. The distortion image collected in Lao Si Cheng ruin which is in the Zhang Jiajie town Hunan province is corrected through the algorithm proposed on above. The features keep the original geometric characteristics. It verifies the validity of the algorithm. And we extract the spectral of different features to compute the correlation coefficient. The results show that the improved spectral sampling method is

  19. Radar sensitivity and antenna scan pattern study for a satellite-based Radar Wind Sounder (RAWS)

    NASA Technical Reports Server (NTRS)

    Stuart, Michael A.

    1992-01-01

    Modeling global atmospheric circulations and forecasting the weather would improve greatly if worldwide information on winds aloft were available. Recognition of this led to the inclusion of the LAser Wind Sounder (LAWS) system to measure Doppler shifts from aerosols in the planned for Earth Observation System (EOS). However, gaps will exist in LAWS coverage where heavy clouds are present. The RAdar Wind Sensor (RAWS) is an instrument that could fill these gaps by measuring Doppler shifts from clouds and rain. Previous studies conducted at the University of Kansas show RAWS as a feasible instrument. This thesis pertains to the signal-to-noise ratio (SNR) sensitivity, transmit waveform, and limitations to the antenna scan pattern of the RAWS system. A dop-size distribution model is selected and applied to the radar range equation for the sensitivity analysis. Six frequencies are used in computing the SNR for several cloud types to determine the optimal transmit frequency. the results show the use of two frequencies, one higher (94 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) for better penetration in rain, provide ample SNR. The waveform design supports covariance estimation processing. This estimator eliminates the Doppler ambiguities compounded by the selection of such high transmit frequencies, while providing an estimate of the mean frequency. the unambiguous range and velocity computation shows them to be within acceptable limits. The design goal for the RAWS system is to limit the wind-speed error to less than 1 ms(exp -1). Due to linear dependence between vectors for a three-vector scan pattern, a reasonable wind-speed error is unattainable. Only the two-vector scan pattern falls within the wind-error limits for azimuth angles between 16 deg to 70 deg. However, this scan only allows two components of the wind to be determined. As a result, a technique is

  20. Effectiveness of variable-gain Kalman filter based on angle error calculated from acceleration signals in lower limb angle measurement with inertial sensors.

    PubMed

    Teruyama, Yuta; Watanabe, Takashi

    2013-01-01

    The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors.

  1. Super-Resolution Scanning Laser Microscopy Based on Virtually Structured Detection

    PubMed Central

    Zhi, Yanan; Wang, Benquan; Yao, Xincheng

    2016-01-01

    Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches—including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy—have been established to achieve super-resolution imaging. However, none of these methods is suitable for the super-resolution ophthalmoscopy of retinal structures because of laser safety issues and inevitable eye movements. We recently experimentally validated virtually structured detection (VSD) as an alternative strategy to extend the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost, and phase artifact–free strategy to achieve super-resolution in scanning laser microscopy. In this article we summarize the basic principles of the VSD method, review our demonstrated single-point and line-scan super-resolution systems, and discuss both technical challenges and the potential of VSD-based instrumentation for super-resolution ophthalmoscopy of the retina. PMID:27480461

  2. Structural changes in a Schiff base molecular assembly initiated by scanning tunneling microscopy tip.

    PubMed

    Tomak, A; Bacaksiz, C; Mendirek, G; Sahin, H; Hur, D; Görgün, K; Senger, R T; Birer, Ö; Peeters, F M; Zareie, H M

    2016-08-19

    We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.

  3. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    PubMed

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

  4. A wavelet based algorithm for DTM extraction from airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Yang, Yan; Tian, Qingjiu

    2007-06-01

    The automatic extraction of Digital Terrain Model (DTM) from point clouds acquired by airborne laser scanning (ALS) equipment remains a problem in ALS data filtering nowadays. Many filter algorithms have been developed to remove object points and outliers, and to extract DTM automatically. However, it is difficult to filter in areas where few points have identical morphological or geological features that can present the bare earth. Especially in sloped terrain covered by dense vegetation, points representing bare earth are often identified as noisy data below ground. To extract terrain surface in these areas, a new algorithm is proposed. First, the point clouds are cut into profiles based on a scan line segmentation algorithm. In each profile, a 1D filtering procedure is determined from the wavelet theory, which is superior in detecting high frequency discontinuities. After combining profiles from different directions, an interpolated grid data representing DTM is generated. In order to evaluate the performance of this new approach, we applied it to the data set used in the ISPRS filter test in 2003. 2 samples containing mostly vegetation on slopes have been processed by the proposed algorithm. It can be seen that it filtered most of the objects like vegetation and buildings in sloped area, and smoothed the hilly mountain to be more close to its real terrain surface.

  5. Super-Resolution Scanning Laser Microscopy Based on Virtually Structured Detection.

    PubMed

    Zhi, Yanan; Wang, Benquan; Yao, Xincheng

    2015-01-01

    Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches-including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy-have been established to achieve super-resolution imaging. However, none of these methods is suitable for the super-resolution ophthalmoscopy of retinal structures because of laser safety issues and inevitable eye movements. We recently experimentally validated virtually structured detection (VSD) as an alternative strategy to extend the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost, and phase artifact-free strategy to achieve super-resolution in scanning laser microscopy. In this article we summarize the basic principles of the VSD method, review our demonstrated single-point and line-scan super-resolution systems, and discuss both technical challenges and the potential of VSD-based instrumentation for super-resolution ophthalmoscopy of the retina.

  6. A sensitive charge scanning probe based on silicon single electron transistor

    NASA Astrophysics Data System (ADS)

    Lina, Su; Xinxing, Li; Hua, Qin; Xiaofeng, Gu

    2016-04-01

    Single electron transistors (SETs) are known to be extremely sensitive electrometers owing to their high charge sensitivity. In this work, we report the design, fabrication, and characterization of a silicon-on-insulator-based SET scanning probe. The fabricated SET is located about 10 μm away from the probe tip. The SET with a quantum dot of about 70 nm in diameter exhibits an obvious Coulomb blockade effect measured at 4.1 K. The Coulomb blockade energy is about 18 meV, and the charge sensitivity is in the order of 10-5-10-3 e/Hz1/2. This SET scanning probe can be used to map charge distribution and sense dynamic charge fluctuation in nanodevices or circuits under test, realizing high sensitivity and high spatial resolution charge detection. Project supported by the Instrument Developing Project of the Chinese Academy of Sciences (No. YZ201152), the National Natural Science Foundation of China (No. 11403084), the Fundamental Research Funds for Central Universities (Nos. JUSRP51510, JUDCF12032), and the Graduate Student Innovation Program for Universities of Jiangsu Province (No. CXLX12_0724).

  7. MEMS scanner mirror based system for retina scanning and in eye projection

    NASA Astrophysics Data System (ADS)

    Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Dallmann, Hans-Georg; Schelinski, Uwe; Grüger, Heinrich

    2015-02-01

    Many applications could benefit from miniaturized systems to scan blood vessels behind the retina in the human eye, so called "retina scanning". This reaches from access control to sophisticated security applications and medical devices. High volume systems for consumer applications require low cost and a user friendly operation. For example this includes no need for removal of glasses and self-adjustment, in turn guidance of focus and point of attraction by simultaneous projection for the user. A new system has been designed based on the well-known resonantly driven 2-d scanner mirror of Fraunhofer IPMS. A combined NIR and VIS laser system illuminates the eye through an eye piece designed for an operating distance allowing the use of glasses and granting sufficient field of view. This usability feature was considered to be more important than highest miniaturization. The modulated VIS laser facilitates the projection of an image directly onto the retina. The backscattered light from the continuous NIR laser contains the information of the blood vessels and is detected by a highly sensitive photo diode. A demonstrational setup has been realized including readout and driving electronics. The laser power was adjusted to an eye-secure level. Additional security features were integrated. Test measurements revealed promising results. In a first demonstration application the detection of biometric pattern of the blood vessels was evaluated for issues authentication in.

  8. 3-D ultrasonic strain imaging based on a linear scanning system.

    PubMed

    Huang, Qinghua; Xie, Bo; Ye, Pengfei; Chen, Zhaohong

    2015-02-01

    This paper introduces a 3-D strain imaging method based on a freehand linear scanning mode. We designed a linear sliding track with a position sensor and a height-adjustable holder to constrain the movement of an ultrasound probe in a freehand manner. When moving the probe along the sliding track, the corresponding positional measures for the probe are transmitted via a wireless communication module based on Bluetooth in real time. In a single examination, the probe is scanned in two sweeps in which the height of the probe is adjusted by the holder to collect the pre- and postcompression radio-frequency echoes, respectively. To generate a 3-D strain image, a volume cubic in which the voxels denote relative strains for tissues is defined according to the range of the two sweeps. With respect to the post-compression frames, several slices in the volume are determined and the pre-compression frames are re-sampled to precisely correspond to the post-compression frames. Thereby, a strain estimation method based on minimizing a cost function using dynamic programming is used to obtain the 2-D strain image for each pair of frames from the re-sampled pre-compression sweep and the post-compression sweep, respectively. A software system is developed for volume reconstruction, visualization, and measurement of the 3-D strain images. The experimental results show that high-quality 3-D strain images of phantom and human tissues can be generated by the proposed method, indicating that the proposed system can be applied for real clinical applications (e.g., musculoskeletal assessments).

  9. Thought-based row-column scanning communication board for individuals with cerebral palsy.

    PubMed

    Scherer, Reinhold; Billinger, Martin; Wagner, Johanna; Schwarz, Andreas; Hettich, Dirk Tassilo; Bolinger, Elaina; Lloria Garcia, Mariano; Navarro, Juan; Müller-Putz, Gernot

    2015-02-01

    Impairment of an individual's ability to communicate is a major hurdle for active participation in education and social life. A lot of individuals with cerebral palsy (CP) have normal intelligence, however, due to their inability to communicate, they fall behind. Non-invasive electroencephalogram (EEG) based brain-computer interfaces (BCIs) have been proposed as potential assistive devices for individuals with CP. BCIs translate brain signals directly into action. Motor activity is no longer required. However, translation of EEG signals may be unreliable and requires months of training. Moreover, individuals with CP may exhibit high levels of spontaneous and uncontrolled movement, which has a large impact on EEG signal quality and results in incorrect translations. We introduce a novel thought-based row-column scanning communication board that was developed following user-centered design principles. Key features include an automatic online artifact reduction method and an evidence accumulation procedure for decision making. The latter allows robust decision making with unreliable BCI input. Fourteen users with CP participated in a supporting online study and helped to evaluate the performance of the developed system. Users were asked to select target items with the row-column scanning communication board. The results suggest that seven among eleven remaining users performed better than chance and were consequently able to communicate by using the developed system. Three users were excluded because of insufficient EEG signal quality. These results are very encouraging and represent a good foundation for the development of real-world BCI-based communication devices for users with CP.

  10. Heart region segmentation from low-dose CT scans: an anatomy based approach

    NASA Astrophysics Data System (ADS)

    Reeves, Anthony P.; Biancardi, Alberto M.; Yankelevitz, David F.; Cham, Matthew D.; Henschke, Claudia I.

    2012-02-01

    Cardiovascular disease is a leading cause of death in developed countries. The concurrent detection of heart diseases during low-dose whole-lung CT scans (LDCT), typically performed as part of a screening protocol, hinges on the accurate quantification of coronary calcification. The creation of fully automated methods is ideal as complete manual evaluation is imprecise, operator dependent, time consuming and thus costly. The technical challenges posed by LDCT scans in this context are mainly twofold. First, there is a high level image noise arising from the low radiation dose technique. Additionally, there is a variable amount of cardiac motion blurring due to the lack of electrocardiographic gating and the fact that heart rates differ between human subjects. As a consequence, the reliable segmentation of the heart, the first stage toward the implementation of morphologic heart abnormality detection, is also quite challenging. An automated computer method based on a sequential labeling of major organs and determination of anatomical landmarks has been evaluated on a public database of LDCT images. The novel algorithm builds from a robust segmentation of the bones and airways and embodies a stepwise refinement starting at the top of the lungs where image noise is at its lowest and where the carina provides a good calibration landmark. The segmentation is completed at the inferior wall of the heart where extensive image noise is accommodated. This method is based on the geometry of human anatomy and does not involve training through manual markings. Using visual inspection by an expert reader as a gold standard, the algorithm achieved successful heart and major vessel segmentation in 42 of 45 low-dose CT images. In the 3 remaining cases, the cardiac base was over segmented due to incorrect hemidiaphragm localization.

  11. Holocene Temperature Reconstructions from Arctic Lakes based on Alkenone Paleothermometry and Non-Destructive Scanning Techniques

    NASA Astrophysics Data System (ADS)

    D'Andrea, W. J.; Balascio, N. L.; Bradley, R. S.; Bakke, J.; Gjerde, M.; Kaufman, D. S.; Briner, J. P.; von Gunten, L.

    2014-12-01

    Generating continuous, accurate and quantitative Holocene temperature estimates from the Arctic is an ongoing challenge. In many Arctic regions, tree ring-based approaches cannot be used and lake sediments provide the most valuable repositories for extracting paleotemperature information. Advances in lacustrine alkenone paleothermometry now allow for quantitative reconstruction of lake-water temperature based on the UK37 values of sedimentary alkenones. In addition, a recent study demonstrated the efficacy of non-destructive scanning reflectance spectroscopy in the visible range (VIS-RS) for high-resolution quantitative temperature reconstruction from arctic lake sediments1. In this presentation, I will report a new UK37-based temperature reconstruction and a scanning VIS-RS record (using the RABD660;670 index as a measure of sedimentary chlorin content) from Kulusuk Lake in southeastern Greenland (65.6°N, 37.1°W). The UK37 record reveals a ~3°C increase in summer lake water temperatures between ~10ka and ~7ka followed by sustained warmth until ~4ka and a gradual (~3°C) cooling until ~400 yr BP. The strong correlation between UK37 and RABD660;670 measured in the same sediment core provides further evidence that in arctic lakes where temperature regulates primary productivity, and thereby sedimentary chlorin content, these proxies can be combined to develop high-resolution quantitative temperature records. The Holocene temperature history of Kulusuk Lake determined using this approach corresponds to changes in the size of the glaciers adjacent to the lake, as inferred from sediment minerogenic properties measured with scanning XRF. Glaciers retreated during early Holocene warming, likely disappeared during the period of mid-Holocene warmth, and advanced after 4ka. I will also discuss new UK37 and RABD660;670 reconstructions from northwestern Svalbard and the central Brooks Range of Alaska within the framework of published regional temperature reconstructions and

  12. Voxel-Based Approach for Estimating Urban Tree Volume from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Vonderach, C.; Voegtle, T.; Adler, P.

    2012-07-01

    The importance of single trees and the determination of related parameters has been recognized in recent years, e.g. for forest inventories or management. For urban areas an increasing interest in the data acquisition of trees can be observed concerning aspects like urban climate, CO2 balance, and environmental protection. Urban trees differ significantly from natural systems with regard to the site conditions (e.g. technogenic soils, contaminants, lower groundwater level, regular disturbance), climate (increased temperature, reduced humidity) and species composition and arrangement (habitus and health status) and therefore allometric relations cannot be transferred from natural sites to urban areas. To overcome this problem an extended approach was developed for a fast and non-destructive extraction of branch volume, DBH (diameter at breast height) and height of single trees from point clouds of terrestrial laser scanning (TLS). For data acquisition, the trees were scanned with highest scan resolution from several (up to five) positions located around the tree. The resulting point clouds (20 to 60 million points) are analysed with an algorithm based on voxel (volume elements) structure, leading to an appropriate data reduction. In a first step, two kinds of noise reduction are carried out: the elimination of isolated voxels as well as voxels with marginal point density. To obtain correct volume estimates, the voxels inside the stem and branches (interior voxels) where voxels contain no laser points must be regarded. For this filling process, an easy and robust approach was developed based on a layer-wise (horizontal layers of the voxel structure) intersection of four orthogonal viewing directions. However, this procedure also generates several erroneous "phantom" voxels, which have to be eliminated. For this purpose the previous approach was extended by a special region growing algorithm. In a final step the volume is determined layer-wise based on the extracted

  13. A scene based nonuniformity correction algorithm for line scanning infrared image

    NASA Astrophysics Data System (ADS)

    Fan, Fan; Ma, Yong; Zhou, Bo; Fang, Yu; Han, Jinhui; Liu, Zhe

    2014-11-01

    In this paper, a fast scene based nonuniformity correction algorithm using Landweber iteration is proposed for line scanning infrared imaging systems (LSIR). The method introduces a novel framework of nonuniformity correction for LSIR by optimization. More specifically, first a "desired" image is obtained by an 1D Guassian filter from the corrected image; then a weighted mean square error optimization function is established in each line to minimize the mean square error between the corrected value and "desired" image. Correction parameters update adaptively by Landweber iteration, and then update the desired image. A stopping rule of the framework is also proposed. The quantitative comparisons with other state-of-the-art methods demonstrate that the proposed algorithm has low complexity and is much more robust on fixed-pattern noise reduction in the static scene.

  14. Novel grid-based optical Braille conversion: from scanning to wording

    NASA Astrophysics Data System (ADS)

    Yoosefi Babadi, Majid; Jafari, Shahram

    2011-12-01

    Grid-based optical Braille conversion (GOBCO) is explained in this article. The grid-fitting technique involves processing scanned images taken from old hard-copy Braille manuscripts, recognising and converting them into English ASCII text documents inside a computer. The resulted words are verified using the relevant dictionary to provide the final output. The algorithms employed in this article can be easily modified to be implemented on other visual pattern recognition systems and text extraction applications. This technique has several advantages including: simplicity of the algorithm, high speed of execution, ability to help visually impaired persons and blind people to work with fax machines and the like, and the ability to help sighted people with no prior knowledge of Braille to understand hard-copy Braille manuscripts.

  15. A new form measurement system based on subaperture stitching with a line-scanning interferometer

    NASA Astrophysics Data System (ADS)

    Laubach, Sören; Ehret, Gerd; Riebeling, Jörg; Lehmann, Peter

    2016-12-01

    A new optical form measurement system for almost rotational symmetric surfaces has been set up. It is based on an interferometric line sensor applying sinusoidal path length modulation in combination with a movement system. With this system, ring-shaped subapertures of the specimens are measured. The system is especially suitable for measuring spheres and aspheres with a broad range of radii (r>50 mm). The individual subapertures are stitched together to yield the full 3D topography. Because the rotation of the specimen by more than 360° has to yield the same results, inherent consistency tests are possible. Example measurements of a sphere are shown and discussed. Reproducibility measurements for one ring scan performed with the system show a standard deviation of 14 nm. The system can be set up at a moderate price as off-the-shelf mechanical and optoelectronic devices can be used. Future improvements of the system are discussed.

  16. Detecting degradation in Ni-based superalloy Udimet520 with scanning SQUID microscopy

    NASA Astrophysics Data System (ADS)

    Isawa, K.; Igarashi, Y.; Hayashi, M.; Sato, F.; Ogota, S.; Hasegawa, S.; Miyaguchi, K.

    2010-11-01

    In order to develop a new method for detecting degradation nondestructively in Udimet520 (U520), which is used for blades of aircraft jet-engine components and land-based gas turbines, fractured and interrupted samples in low-cycle fatigue (LCF) and creep tests were studied using scanning SQUID microscopy (SSM). High temperature LCF and creep experiments on U520 were conducted to obtain various samples with different damage level. Simultaneously, we also examined the artificially degraded samples by optical microscopy, electron backscattering diffraction, and hardness measurements to ensure the damage level. On the basis of the magnetic permeability data, the virgin sample is nonmagnetic. However, for the artificially damaged samples, the observation of magnetic signals on the field maps indicates the potential of SSM to evaluate the degradation in U520 superalloy nondestructively.

  17. High-speed, image-based eye tracking with a scanning laser ophthalmoscope

    PubMed Central

    Sheehy, Christy K.; Yang, Qiang; Arathorn, David W.; Tiruveedhula, Pavan; de Boer, Johannes F.; Roorda, Austin

    2012-01-01

    We demonstrate a high-speed, image-based tracking scanning laser ophthalmoscope (TSLO) that can provide high fidelity structural images, real-time eye tracking and targeted stimulus delivery. The system was designed for diffraction-limited performance over an 8° field of view (FOV) and operates with a flexible field of view of 1°–5.5°. Stabilized videos of the retina were generated showing an amplitude of motion after stabilization of 0.2 arcmin or less across all frequencies. In addition, the imaging laser can be modulated to place a stimulus on a targeted retinal location. We show a stimulus placement accuracy with a standard deviation less than 1 arcmin. With a smaller field size of 2°, individual cone photoreceptors were clearly visible at eccentricities outside of the fovea. PMID:23082300

  18. A Dummy Scan Flip-Flop Insertion Algorithm based on Driving Vertex

    NASA Astrophysics Data System (ADS)

    Liu, H. L.; Li, L.; Zhang, Z. X.; Zhou, W. T.

    2017-03-01

    Commonly termed as Hardware Trojans, is an emerging issue for global hardware security. The research on Hardware Trojan detection is urgent and significant. Dummy Scan Flip-Flop(DSFF) structure could be used to improve the probability of hardware Trojan activation, which is significant to hardware Trojan detection, especially during the design phase. In this express, an algorithm for inserting the DSFF structure based on driving vertex is proposed. According to the experimental results, under the same transition probability threshold(Pth), compared to the state-of-art, the proposed algorithm can reduce both the inserting complexity and the induced area overhead of the DSFF insertion. The maximum area optimization rate can reach 44.8%. The simulation results on S386 and S38584 benchmark circuits indicate that the proposed algorithm can significantly reduce Trojan authentication time by increasing activation probability of hardware Trojan circuits.

  19. Decoupling criterion based on limited energy loss condition for groove measurement using optical scanning microscopes

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Li, Mengzhou; Li, Qiang; Tan, Jiubin

    2016-12-01

    In confocal metrology, the lateral and axial responses are coupled in narrow regions near groove edges. This coupling results in an area with an uncertain profile, particularly for measurements of tight structures or deep grooves. In this paper, to delineate the area with measurement accuracy loss, an analytical model depicting the coupling relationships between the groove depth, the coupled portions and the NA of the objective used is introduced. Based on this model, the limited energy lost (LEL) decoupling criterion is presented that can enable users to choose suitable numerical apertures before performing measurements, predict the extents of the areas with measurement accuracy loss, and identify readout areas that yield accurate height measurements. The theory was verified by using confocal microscopes and is also applicable to far-field optical scanning metrology.

  20. A simple scanning spectrometer based on a stretchable elastomeric reflective grating

    SciTech Connect

    Ghisleri, C.; Milani, P.; Potenza, M. A. C.; Bellacicca, A.; Ravagnan, L.

    2014-02-10

    We report a scanning optical spectrometer based on the use of a stretchable elastomeric reflective grating. The grating is obtained by supersonic cluster beam implantation of silver nanoparticles on polydimethylsiloxane previously grooved by molding to create a replica of a commercial digital versatile disk grating. The use of a stretchable grating allows the spectrometer spanning the whole optical wavelength range by solely extending the diffraction element by more than 100% of its original dimensions. The stretchable reflective optical grating shows excellent performances and stability upon thousands of stretching cycles. The use of this elastomeric element makes the optical layout and the mechanics of the spectrometer extremely simple and advantageous for those applications where spectral resolution is not a major requirement. As a proof of principle, we present the absorption spectrum of Rhodamine B in solution obtained by our spectrometer and compared to commercial instruments.

  1. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity.

    PubMed

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-07-03

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach.

  2. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

    PubMed Central

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-01-01

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach. PMID:26151203

  3. Morphology-based three-dimensional segmentation of coronary artery tree from CTA scans

    NASA Astrophysics Data System (ADS)

    Banh, Diem Phuc T.; Kyprianou, Iacovos S.; Paquerault, Sophie; Myers, Kyle J.

    2007-03-01

    We developed an algorithm based on a rule-based threshold framework to segment the coronary arteries from angiographic computed tomography (CTA) data. Computerized segmentation of the coronary arteries is a challenging procedure due to the presence of diverse anatomical structures surrounding the heart on cardiac CTA data. The proposed algorithm incorporates various levels of image processing and organ information including region, connectivity and morphology operations. It consists of three successive stages. The first stage involves the extraction of the three-dimensional scaffold of the heart envelope. This stage is semiautomatic requiring a reader to review the CTA scans and manually select points along the heart envelope in slices. These points are further processed using a surface spline-fitting technique to automatically generate the heart envelope. The second stage consists of segmenting the left heart chambers and coronary arteries using grayscale threshold, size and connectivity criteria. This is followed by applying morphology operations to further detach the left and right coronary arteries from the aorta. In the final stage, the 3D vessel tree is reconstructed and labeled using an Isolated Connected Threshold technique. The algorithm was developed and tested on a patient coronary artery CTA that was graciously shared by the Department of Radiology of the Massachusetts General Hospital. The test showed that our method constantly segmented the vessels above 79% of the maximum gray-level and automatically extracted 55 of the 58 coronary segments that can be seen on the CTA scan by a reader. These results are an encouraging step toward our objective of generating high resolution models of the male and female heart that will be subsequently used as phantoms for medical imaging system optimization studies.

  4. A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

    NASA Astrophysics Data System (ADS)

    Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

    2017-03-01

    The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg–Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

  5. A servomechanism for a micro-electro-mechanical-system-based scanning-probe data storage device

    NASA Astrophysics Data System (ADS)

    Pantazi, A.; Lantz, M. A.; Cherubini, G.; Pozidis, H.; Eleftheriou, E.

    2004-10-01

    Micro-electro-mechanical-system (MEMS)-based scanning-probe data storage devices are emerging as potential ultra-high-density, low-access-time, and low-power alternatives to conventional data storage. One implementation of probe-based storage uses thermomechanical means to store and retrieve information in thin polymer films. One of the challenges in building such devices is the extreme accuracy and the short latency required in the navigation of the probes over the polymer medium. This paper focuses on the design and characterization of a servomechanism to achieve such accurate positioning in a probe-based storage prototype. In our device, the polymer medium is positioned on a MEMS scanner with x/y-motion capabilities of about 100 µm. The device also includes thermal position sensors that provide x/y-position information to the servo controller. Based on a discrete state-space model of the scanner dynamics, a controller is designed using the linear quadratic Gaussian approach with state estimation. The random seek performance of this approach is evaluated and compared with that of the conventional proportional, integrator, and derivative (PID) approach. The results demonstrate the superiority of the state-space approach, which achieves seek times of about 4 ms in a ± 50 µm range. Finally, the experimental results show that closed-loop track following using the thermal position-sensor signals is feasible and yields a position-error standard deviation of approximately 2 nm.

  6. A novel target LOS calibration method for IR scanning sensor based on control points

    NASA Astrophysics Data System (ADS)

    Xue, Yong-Hong; An, Wei; Zhang, Yin-Sheng; Zhang, Tao

    2012-12-01

    Space based IR system uses the information of target LOS (line of sight) for target location. Recent researches show that the measuring precision of target LOS is usually determined by measuring precision of platform's position and attitude, and deformation of sensor etc. Most methods for improving target location precision are either through improving platform's position and attitude measuring precision or through calib rating the whole image obtained by IR sensor. With the development of measuring technology, it is harder to make a further improvement on the measuring precision of position and attitude of the platform and the expansion of the sensor view make calibrat ion of the whole image with a larger computation cost. In this paper, a method using control points to calibrate target LOS was proposed. Based on the analysis of the imaging process of the scanning sensor of space based IR system, this paper established a modify model of target LOS based on control points, used a bias filter to estimate the bias value of sensor boresight, and finally achieved the mission of target LOS calibrat ion. Different from the traditional calibration method of remote sensing image, the proposed method only made a correct ion on the LOS of suspicious target, but not established the accurate relationship between the all pixels and their real location, and has a similar calibration performance, but more lower computational complexity.

  7. Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices

    PubMed Central

    Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

    2015-01-01

    In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given. PMID:26703624

  8. Climatology and trends of mesospheric (58-90) temperatures based upon 1982-1986 SME limb scattering profiles

    NASA Technical Reports Server (NTRS)

    Clancy, R. Todd; Rusch, David W.

    1989-01-01

    Atmospheric temperature profiles for the altitude range 58-90 km were calculated using data on global UV limb radiances from the SME satellite. The major elements of this climatology include a high vertical resolution (about 4 km) and the coverage of the 70-90 km altitude region. The analysis of this extensive data set provides a global definition of mesospheric-lower thermospheric temperature trends over the 1982-1986 period. The observations suggest a pattern of 1-2 K/year decreases in temperatures at 80-90-km altitudes accompanied by 0.5-1.5 K/year increases in temperatures at 65-80-km altitudes.

  9. Diameter distribution estimation with laser scanning based multisource single tree inventory

    NASA Astrophysics Data System (ADS)

    Kankare, Ville; Liang, Xinlian; Vastaranta, Mikko; Yu, Xiaowei; Holopainen, Markus; Hyyppä, Juha

    2015-10-01

    Tree detection and tree species recognition are bottlenecks of the airborne remote sensing-based single tree inventories. The effect of these factors in forest attribute estimation can be reduced if airborne measurements are aided with tree mapping information that is collected from the ground. The main objective here was to demonstrate the use of terrestrial laser scanning-derived (TLS) tree maps in aiding airborne laser scanning-based (ALS) single tree inventory (multisource single tree inventory, MS-STI) and its capability in predicting diameter distribution in various forest conditions. Automatic measurement of TLS point clouds provided the tree maps and the required reference information from the tree attributes. The study area was located in Evo, Finland, and the reference data was acquired from 27 different sample plots with varying forest conditions. The workflow of MS-STI included: (1) creation of automatic tree map from TLS point clouds, (2) automatic diameter at breast height (DBH) measurement from TLS point clouds, (3) individual tree detection (ITD) based on ALS, (4) matching the ITD segments to the field-measured reference, (5) ALS point cloud metric extraction from the single tree segments and (6) DBH estimation based on the derived metrics. MS-STI proved to be accurate and efficient method for DBH estimation and predicting diameter distribution. The overall accuracy (root mean squared error, RMSE) of the DBH was 36.9 mm. Results showed that the DBH accuracy decreased if the tree density (trees/ha) increased. The highest accuracies were found in old-growth forests (tree densities less than 500 stems/ha). MS-STI resulted in the best accuracies regarding Norway spruce (Picea abies (L.) H. Karst.)-dominated forests (RMSE of 29.9 mm). Diameter distributions were predicted with low error indices, thereby resulting in a good fit compared to the reference. Based on the results, diameter distribution estimation with MS-STI is highly dependent on the forest

  10. Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ-based CT scan planning

    SciTech Connect

    Yin, Zhye De Man, Bruno; Yao, Yangyang; Wu, Mingye; Montillo, Albert; Edic, Peter M.; Kalra, Mannudeep

    2015-05-15

    Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies to achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors’ pictorial-structures based organ localization algorithm successfully located the major abdominal-thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.

  11. Multiresolution scanning imager with spatially uniform noise response based on a new class of Hadamard masks

    NASA Astrophysics Data System (ADS)

    Bone, Donald J.; Popescu, Dan C.

    2000-05-01

    In spite the prodigious growth in the market for digital cameras, they have yet to displace film-based cameras in the consumer market. This is largely due to the high cost of photographic resolution sensors. One possible approach to producing a low cost, high resolution sensor is to linearly scan a masked low resolution sensor. Masking of the sensor elements allows transform domain imaging. Multiple displaced exposures of such a masked sensor permits the device to acquire a linear transform of a higher resolution representation of the image than that defined by the sensor element dimensions. Various approaches have been developed in the past along these lines, but they often suffer from poor sensitivity, difficulty in being adapted to a 2D sensor or spatially variable noise response. This paper presents an approach based on a new class of Hadamard masks--Uniform Noise Hadamard Masks--which has superior sensitivity to simple sampling approaches and retains the multiresolution capabilities of certain Hadamard matrices, while overcoming the non-uniform noise response problems of some simple Hadamard based masks.

  12. Drying techniques for the visualisation of agarose-based chromatography media by scanning electron microscopy.

    PubMed

    Nweke, Mauryn C; Turmaine, Mark; McCartney, R Graham; Bracewell, Daniel G

    2017-03-01

    The drying of chromatography resins prior to scanning electron microscopy is critical to image resolution and hence understanding of the bead structure at sub-micron level. Achieving suitable drying conditions is especially important with agarose-based chromatography resins, as over-drying may cause artefact formation, bead damage and alterations to ultrastructural properties; and under-drying does not provide sufficient resolution for visualization under SEM. This paper compares and contrasts the effects of two drying techniques, critical point drying and freeze drying, on the morphology of two agarose based resins (MabSelect™/dw ≈85 µm and Capto™ Adhere/dw ≈75 µm) and provides a complete method for both. The results show that critical point drying provides better drying and subsequently clearer ultrastructural visualization of both resins under SEM. Under this protocol both the polymer fibers (thickness ≈20 nm) and the pore sizes (diameter ≈100 nm) are clearly visible. Freeze drying is shown to cause bead damage to both resins, but to different extents. MabSelect resin encounters extensive bead fragmentation, whilst Capto Adhere resin undergoes partial bead disintegration, corresponding with the greater extent of agarose crosslinking and strength of this resin. While freeze drying appears to be the less favorable option for ultrastructural visualization of chromatography resin, it should be noted that the extent of fracturing caused by the freeze drying process may provide some insight into the mechanical properties of agarose-based chromatography media.

  13. Plasma etched surface scanning inspection recipe creation based on bidirectional reflectance distribution function and polystyrene latex spheres

    NASA Astrophysics Data System (ADS)

    Saldana, Tiffany; McGarvey, Steve; Ayres, Steve

    2014-04-01

    The continual increasing demands upon Plasma Etching systems to self-clean and continue Plasma Etching with minimal downtime allows for the examination of SiCN, SiO2 and SiN defectivity based upon Surface Scanning Inspection Systems (SSIS) wafer scan results. Historically all Surface Scanning Inspection System wafer scanning recipes have been based upon Polystyrene Spheres wafer deposition for each film stack and the subsequent creation of light scattering sizing response curves. This paper explores the feasibility of the elimination of Polystyrene Latex Sphere (PSL) and/or process particle deposition on both filmed and bare Silicon wafers prior to Surface Scanning Inspection System recipe creation. The study will explore the theoretical maximal Surface Scanning Inspection System sensitivity based on PSL recipe creation in conjunction with the maximal sensitivity derived from Bidirectional Reflectance Distribution Function (BRDF) maximal sensitivity modeling recipe creation. The surface roughness (Root Mean Square) of plasma etched wafers varies dependent upon the process film stack. Decrease of the root mean square value of the wafer sample surface equates to higher surface scanning inspection system sensitivity. Maximal sensitivity SSIS scan results from bare and filmed wafers inspected with recipes created based upon Polystyrene/Particle Deposition and recipes created based upon BRDF modeling will be overlaid against each other to determine maximal sensitivity and capture rate for each type of recipe that was created with differing recipe creation modes. A statistically valid sample of defects from each Surface Scanning Inspection system recipe creation mode and each bare wafer/filmed substrate will be reviewed post SSIS System processing on a Defect Review Scanning Electron Microscope (DRSEM). Native defects, Polystyrene Latex Spheres will be collected from each statistically valid defect bin category/size. The data collected from the DRSEM will be utilized to

  14. Neuronal injury in the motor cortex after chronic stroke and lower limb motor impairment: a voxel-based lesion symptom mapping study.

    PubMed

    Reynolds, Alexandria M; Peters, Denise M; Vendemia, Jennifer M C; Smith, Lenwood P; Sweet, Raymond C; Baylis, Gordon C; Krotish, Debra; Fritz, Stacy L

    2014-04-01

    Many studies have examined motor impairments using voxel-based lesion symptom mapping, but few are reported regarding the corresponding relationship between cerebral cortex injury and lower limb motor impairment analyzed using this technique. This study correlated neuronal injury in the cerebral cortex of 16 patients with chronic stroke based on a voxel-based lesion symptom mapping analysis. Neuronal injury in the corona radiata, caudate nucleus and putamen of patients with chronic stroke could predict walking speed. The behavioral measure scores were consistent with motor deficits expected after damage to the cortical motor system due to stroke. These findings suggest that voxel-based lesion symptom mapping may provide a more accurate prognosis of motor recovery from chronic stroke according to neuronal injury in cerebral motor cortex.

  15. Neuronal injury in the motor cortex after chronic stroke and lower limb motor impairment: a voxel-based lesion symptom mapping study

    PubMed Central

    Reynolds, Alexandria M.; Peters, Denise M.; Vendemia, Jennifer M. C.; Smith, Lenwood P.; Sweet, Raymond C.; Baylis, Gordon C.; Krotish, Debra; Fritz, Stacy L.

    2014-01-01

    Many studies have examined motor impairments using voxel-based lesion symptom mapping, but few are reported regarding the corresponding relationship between cerebral cortex injury and lower limb motor impairment analyzed using this technique. This study correlated neuronal injury in the cerebral cortex of 16 patients with chronic stroke based on a voxel-based lesion symptom mapping analysis. Neuronal injury in the corona radiata, caudate nucleus and putamen of patients with chronic stroke could predict walking speed. The behavioral measure scores were consistent with motor deficits expected after damage to the cortical motor system due to stroke. These findings suggest that voxel-based lesion symptom mapping may provide a more accurate prognosis of motor recovery from chronic stroke according to neuronal injury in cerebral motor cortex. PMID:25206888

  16. C-scan transmission ultrasound based on a hybrid microelectronic sensor array and its physical performance

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Rich, David; Lasser, Marvin E.; Kula, John; Zhao, Hui; Lasser, Bob; Freedman, Matthew T.

    2001-05-01

    A C-scan through-transmission ultrasound system has been constructed based on a patented hybrid microelectronic array that is capable of generating ultrasound images with fluoroscopic presentation. To generate real-time images, ultrasound is introduced into the object under study with a large unfocused plane wave source. The resultant pressure wave strikes the object and is attenuated and scattered. The device detects scattered as well as attenuated ultrasound energy which allows the use of an acoustic lens to focus on detected energy from an object plane. The acoustic lens collects the transmitted energy and focuses it onto the ultrasound sensitive array. The array is made up to two components, a silicon detector/readout array and a piezoelectric material that is deposited onto the array through semiconductor processing. The array is 1 cm on a side consisting of 128x128 pixel elements with 85micrometers pixel spacing. The energy that strikes the piezoelectric material is converted to an analog voltage that is digitized and processed by low cost commercial video electronics. The images generated by the device appear with no speckle artifact with fluoroscopy-like presentation. The images show no obvious geometrical distortion. The experimental results indicated that the system has a spatial resolution of 0.32 mm. It can resolve 3mm objects with low differential contrast and an attenuation coefficient difference less than 0.07 dB/cm/MHz. Phase contrast of the objects are also clearly measurable. A presentation of a C- scan image guided breast biopsy was demonstrated. In addition, punctured needle tracks in a tumor was clearly observed. This implies the potential of observing the spiculation of masses in vivo.

  17. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat

    SciTech Connect

    Hackley, Jason D.; Kislitsyn, Dmitry A.; Beaman, Daniel K.; Nazin, George V.; Ulrich, Stefan

    2014-10-15

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  18. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat.

    PubMed

    Hackley, Jason D; Kislitsyn, Dmitry A; Beaman, Daniel K; Ulrich, Stefan; Nazin, George V

    2014-10-01

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  19. Upper limb prosthetic outcome measures: review and content comparison based on International Classification of Functioning, Disability and Health.

    PubMed

    Lindner, Helen Y N; Nätterlund, Birgitta Sjöqvist; Hermansson, Liselotte M Norling

    2010-06-01

    The International Classification of Functioning, Disability and Health (ICF) has been recommended as a framework for evaluation of aspects of health. The aim of this study was to compare the contents of outcome measures for upper limb prosthesis users by using the ICF. Measurement focus and psychometric properties of these measures were also investigated. Outcome measures that used upper limb prosthesis users as subjects in their development and psychometric evaluations were selected. The psychometric studies (n = 14) were reviewed and scored and the items in the measures were linked to the ICF. One measure for all ages (ACMC), five paediatric measures (CAPP-FSI, CAPP-PSI, PUFI, UBET and UNB) and two adult measures (OPUS and TAPES) were selected. The concepts extracted (n = 393) were linked to 54 categories in the ICF. The ACMC, CAPP-FSI, UBET, UNB and PUFI measure categories mostly under the ICF component 'Activity and participation'. The TAPES and OPUS also measure ICF categories that describe the emotional and social status of a person. The main conclusion is that the use of a mixture of outcome measures would give a better picture on the aspects of our clients. Measures that focus on the social interaction in paediatric users are required.

  20. Image distortion and its correction in linear galvanometric mirrors-based laser-scanning microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Wu, Zhenguo; Zeng, Haishan

    2015-05-01

    To simplify imaging focusing and calibration tasks, a laser-scanning microscope needs to scan at a moderate frame rate. The inertia of a galvanometric scanner leads to time delays when following external commands, which subsequently introduces image distortions that deteriorate as scan frequency increases. Sinusoidal and triangular waveforms were examined as fast axis driving patterns. The interplay among driving pattern, frequency, sampling rate, phase shift, linear scanning range, and their effect on reconstructed images was discussed. Utilizing position feedback from the linear galvo scanners, the effect of response time could be automatically compensated in real time. Precompensated triangular driving waveform offered the least amount of image distortion.

  1. Is there an ideal set of prospective scan acquisition phases for fast-helical based 4D-CT?

    NASA Astrophysics Data System (ADS)

    Thomas, D. H.; Ruan, D.; Williams, P.; Lamb, J.; White, B. M.; Dou, T.; O'Connell, D.; Lee, P.; Low, D. A.

    2016-12-01

    The article aims to determine if a prospective acquisition algorithm can be used to find the ideal set of free-breathing phases for fast-helical model-based 4D-CT. A retrospective five-patient dataset that consisted of 25 repeated free breathing CT scans per patient was used. The sum of the square root amplitude difference between all the breathing phases was defined as an objective function to determine the optimality of sets of breathing phases. The objective function was intended to determine if a specific set of breathing phases would yield a motion model that could accurately predict the motion in all 25 CT scans. Voxel specific motion models were calculated using all combinations of N scans from 25 breathing trajectories, (3  ⩽  N  ⩽  25), and the minimum number of scans required to absolutely characterize the motion model was analyzed. This analysis suggests that the number of scans could potentially be reduced to as few as five scans. When the objective function was large, the resulting motion model provided an excellent approximation to the motion model created using all 25 scans.

  2. LIMB Demonstration Project Extension

    SciTech Connect

    Not Available

    1988-03-15

    The basic goal of the Limestone Injection Multistage Burner (LIMB) demonstration is to extend LIMB technology development to a full-scale application on a representative wall-fired utility boiler. The successful retrofit of LIMB to an existing boiler is expected to demonstrate that (a) reductions of 50 percent or greater in SO{sub x} and NO{sub x} emissions can be achieved at a fraction of the cost of add-on FGD systems, (b) boiler reliability, operability, and steam production can be maintained at levels existing prior to LIMB retrofit, and (c) technical difficulties attributable to LIMB operation, such as additional slagging and fouling, changes in ash disposal requirements, and an increased particulate load, can be resolved in a cost-effective manner. The primary fuel to be used will be an Ohio bituminous coal having a nominal sulfur content of 3 percent or greater.

  3. LIMB Demonstration Project Extension

    SciTech Connect

    Not Available

    1988-09-15

    The basic goal of the Limestone Injection Multistage Burner (LIMB) demonstration is to extend LIMB technology development to a full-scale application on a representative wall-fired utility boiler. The successful retrofit of LIMB to an existing boiler is expected to demonstrate that (a) reductions of 50 percent or greater in SO and NO emissions can be achieved at a fraction of the cost of add-on FGD systems, (b) boiler reliability, operability, and steam production can be maintained at levels existing prior to LIMB retrofit, and (c) technical difficulties attributable to LIMB operation, such as additional slagging and fouling, changes in ash disposal requirements, and an increased particulate load, can be resolved in a cost-effective manner. The primary fuel to be used will be an Ohio bituminous coal having a nominal sulfur content of 3 percent or greater.

  4. α-Information-Based Registration of Dynamic Scans for Magnetic Resonance Cystography.

    PubMed

    Han, Hao; Lin, Qin; Li, Lihong; Duan, Chaijie; Lu, Hongbing; Li, Haifang; Yan, Zengmin; Fitzgerald, John; Liang, Zhengrong

    2016-07-01

    To continue our effort on developing magnetic resonance (MR) cystography, we introduce a novel nonrigid 3-D registration method to compensate for bladder wall motion and deformation in dynamic MR scans, which are impaired by relatively low signal-to-noise ratio in each time frame. The registration method is developed on the similarity measure of α-information, which has the potential of achieving higher registration accuracy than the commonly used mutual information (MI) measure for either monomodality or multimodality image registration. The α-information metric was also demonstrated to be superior to both the mean squares and the cross-correlation metrics in multimodality scenarios. The proposed α-registration method was applied for bladder motion compensation via real patient studies, and its effect to the automatic and accurate segmentation of bladder wall was also evaluated. Compared with the prevailing MI-based image registration approach, the presented α-information-based registration was more effective to capture the bladder wall motion and deformation, which ensured the success of the following bladder wall segmentation to achieve the goal of evaluating the entire bladder wall for detection and diagnosis of abnormality.

  5. Structure and characteristics of community-based multidisciplinary wound care teams in Ontario: an environmental scan.

    PubMed

    Abrahamyan, Lusine; Wong, Josephine; Pham, Ba'; Trubiani, Gina; Carcone, Steven; Mitsakakis, Nicholas; Rosen, Laura; Rac, Valeria E; Krahn, Murray

    2015-01-01

    Multidisciplinary team approach is an essential component of evidence-based wound management in the community. The objective of this study was to identify and describe community-based multidisciplinary wound care teams in Ontario. For the study, a working definition of a multidisciplinary wound care team was developed, and a two-phase field evaluation was conducted. In phase I, a systematic survey with three search strategies (environmental scan) was conducted to identify all multidisciplinary wound care teams in Ontario. In phase II, the team leads were surveyed about the service models of the teams. We identified 49 wound care teams in Ontario. The highest ratio of Ontario seniors to wound team within each Ontario health planning region was 82,358:1; the lowest ratio was 14,151:1. Forty-four teams (90%) participated in the survey. The majority of teams existed for at least 5 years, were established as hospital outpatient clinics, and served patients with chronic wounds. Teams were heterogeneous in on-site capacity of specialized diagnostic testing and wound treatment, team size, and patient volume. Seventy-seven percent of teams had members from three or more disciplines. Several teams lacked essential disciplines. More research is needed to identify optimal service models leading to improved patient outcomes.

  6. Development of a prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD)

    NASA Astrophysics Data System (ADS)

    Garrity, D. J.; De Rosa, A. J.; Bradley, D. A.; Jarman, S. E.; Jenneson, P. M.; Vincent, S. M.

    2010-07-01

    A prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD) has been produced, for which system development and preliminary results are presented here. This apparatus has been developed from experience with 2D and 3D bench-top EDXRD systems and comprises a conventional industrial X-ray tube coupled to a bespoke design of tungsten collimators and compact CdTe detector. It is designed as a robust system, rather than delicate lab-based system, to investigate sections of stainless steel pipework for structural changes induced through quenching the steel in liquid nitrogen, and damaging effects such as chloride-induced stress corrosion cracking (SCC). Given the properties of tungsten, namely its brittle nature, a complex programme of electro-discharge machining (EDM) has been devised to precisely manufacture the collimators from a series of sintered tungsten blocks. Preliminary measurements have focused on calibrating the system using the extreme ferrite and austenite phases, meeting a pre-requisite benchmark for attempting more challenging measurements such as the austenite to martensite transformation and investigations of SCC in these sections of pipework.

  7. Correction of image distortions in endoscopic optical coherence tomography based on two-axis scanning MEMS mirrors

    PubMed Central

    Wang, Donglin; Liang, Peng; Samuelson, Sean; Jia, Hongzhi; Ma, Junshan; Xie, Huikai

    2013-01-01

    A two-axis scanning microelectromechanical (MEMS) mirror enables an optical coherence tomography (OCT) system to perform three-dimensional endoscopic imaging due to its fast scan speed and small size. However, the radial scan from the MEMS mirror causes various distortions in OCT images, namely spherical, fan-shaped and keystone distortions. In this paper, a new method is proposed to correct all of three distortions presented in OCT systems based on two-axis MEMS scanning mirrors. The spherical distortion is corrected first by directly manipulating the original spectral interferograms in the phase domain, followed by Fourier transform and three-dimensional geometrical transformation for correcting the other two types of distortions. OCT imaging experiments on a paper with square ink printed arrays and a glass tube filled with milk have been used to validate the proposed method. Distortions in OCT images of flat or curved surfaces can all be effectively removed. PMID:24156064

  8. Nuclear Scans

    MedlinePlus

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  9. WBC scan

    MedlinePlus

    ... in the body. It is a type of nuclear scan . How the Test is Performed Blood will ... radiation. Due to the slight radiation exposure, most nuclear scans (including WBC scan) are not recommended for ...

  10. Liver scan

    MedlinePlus

    ... Nuclear scan - technetium; Nuclear scan - liver or spleen Images Liver scan References Lidofsky S. Jaundice. In: Feldman M, ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  11. PET scan

    MedlinePlus

    ... may have an allergic reaction to the tracer material. Some people have pain, redness, or swelling at ... with diabetes. Most PET scans are now performed along with a CT scan. This combination scan ...

  12. Biomechanical consideration based on the unrestrained gait measurement of trans-femoral amputee with a prosthetic limb.

    PubMed

    Hayashi, Yuichiro; Tsujiuchi, Nobutaka; Koizumi, Takayuki; Matsuda, Yasushi; Tsuchiya, Youtaro

    2011-01-01

    Trans-femoral amputees must regain moving pattern by refined rehabilitation program using loads applied on a prosthetic limb. On the other hand, understanding those loads is indispensable for biomechanical consideration of trans-femoral amputees. However, conventional prosthetic gait training systems cannot measure long continuous walking motions. In this paper, loads applied on trans-femoral prosthesis are measured by the prosthetic gait training system for the unrestrained gait measurement. As a result of the experiments, the patterns of moments about the medio-lateral axis are remarkably different among the six activities. Finally, the effectiveness of the developed prosthetic gait training system to analyze biomechanics in trans-femoral prosthesis is validated.

  13. Comparison of sEMG-Based Feature Extraction and Motion Classification Methods for Upper-Limb Movement

    PubMed Central

    Guo, Shuxiang; Pang, Muye; Gao, Baofeng; Hirata, Hideyuki; Ishihara, Hidenori

    2015-01-01

    The surface electromyography (sEMG) technique is proposed for muscle activation detection and intuitive control of prostheses or robot arms. Motion recognition is widely used to map sEMG signals to the target motions. One of the main factors preventing the implementation of this kind of method for real-time applications is the unsatisfactory motion recognition rate and time consumption. The purpose of this paper is to compare eight combinations of four feature extraction methods (Root Mean Square (RMS), Detrended Fluctuation Analysis (DFA), Weight Peaks (WP), and Muscular Model (MM)) and two classifiers (Neural Networks (NN) and Support Vector Machine (SVM)), for the task of mapping sEMG signals to eight upper-limb motions, to find out the relation between these methods and propose a proper combination to solve this issue. Seven subjects participated in the experiment and six muscles of the upper-limb were selected to record sEMG signals. The experimental results showed that NN classifier obtained the highest recognition accuracy rate (88.7%) during the training process while SVM performed better in real-time experiments (85.9%). For time consumption, SVM took less time than NN during the training process but needed more time for real-time computation. Among the four feature extraction methods, WP had the highest recognition rate for the training process (97.7%) while MM performed the best during real-time tests (94.3%). The combination of MM and NN is recommended for strict real-time applications while a combination of MM and SVM will be more suitable when time consumption is not a key requirement. PMID:25894941

  14. Training modalities in robot-mediated upper limb rehabilitation in stroke: a framework for classification based on a systematic review.

    PubMed

    Basteris, Angelo; Nijenhuis, Sharon M; Stienen, Arno H A; Buurke, Jaap H; Prange, Gerdienke B; Amirabdollahian, Farshid

    2014-07-10

    Robot-mediated post-stroke therapy for the upper-extremity dates back to the 1990s. Since then, a number of robotic devices have become commercially available. There is clear evidence that robotic interventions improve upper limb motor scores and strength, but these improvements are often not transferred to performance of activities of daily living. We wish to better understand why. Our systematic review of 74 papers focuses on the targeted stage of recovery, the part of the limb trained, the different modalities used, and the effectiveness of each. The review shows that most of the studies so far focus on training of the proximal arm for chronic stroke patients. About the training modalities, studies typically refer to active, active-assisted and passive interaction. Robot-therapy in active assisted mode was associated with consistent improvements in arm function. More specifically, the use of HRI features stressing active contribution by the patient, such as EMG-modulated forces or a pushing force in combination with spring-damper guidance, may be beneficial.Our work also highlights that current literature frequently lacks information regarding the mechanism about the physical human-robot interaction (HRI). It is often unclear how the different modalities are implemented by different research groups (using different robots and platforms). In order to have a better and more reliable evidence of usefulness for these technologies, it is recommended that the HRI is better described and documented so that work of various teams can be considered in the same group and categories, allowing to infer for more suitable approaches. We propose a framework for categorisation of HRI modalities and features that will allow comparing their therapeutic benefits.

  15. Training modalities in robot-mediated upper limb rehabilitation in stroke: a framework for classification based on a systematic review

    PubMed Central

    2014-01-01

    Robot-mediated post-stroke therapy for the upper-extremity dates back to the 1990s. Since then, a number of robotic devices have become commercially available. There is clear evidence that robotic interventions improve upper limb motor scores and strength, but these improvements are often not transferred to performance of activities of daily living. We wish to better understand why. Our systematic review of 74 papers focuses on the targeted stage of recovery, the part of the limb trained, the different modalities used, and the effectiveness of each. The review shows that most of the studies so far focus on training of the proximal arm for chronic stroke patients. About the training modalities, studies typically refer to active, active-assisted and passive interaction. Robot-therapy in active assisted mode was associated with consistent improvements in arm function. More specifically, the use of HRI features stressing active contribution by the patient, such as EMG-modulated forces or a pushing force in combination with spring-damper guidance, may be beneficial. Our work also highlights that current literature frequently lacks information regarding the mechanism about the physical human-robot interaction (HRI). It is often unclear how the different modalities are implemented by different research groups (using different robots and platforms). In order to have a better and more reliable evidence of usefulness for these technologies, it is recommended that the HRI is better described and documented so that work of various teams can be considered in the same group and categories, allowing to infer for more suitable approaches. We propose a framework for categorisation of HRI modalities and features that will allow comparing their therapeutic benefits. PMID:25012864

  16. Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Helmholz, P.; Belton, D.; West, G.

    2014-04-01

    The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

  17. Accurate Measurement of Brain Changes in Longitudinal MRI Scans using Tensor-Based Morphometry

    PubMed Central

    Hua, Xue; Gutman, Boris; Boyle, Christina; Rajagopalan, Priya; Leow, Alex D.; Yanovsky, Igor; Kumar, Anand R.; Toga, Arthur W.; Jack, Clifford R.; Schuff, Norbert; Alexander, Gene E.; Chen, Kewei; Reiman, Eric M.; Weiner, Michael W.; Thompson, Paul M.

    2011-01-01

    This paper responds to Thompson and Holland (2011), who challenged our tensor-based morphometry (TBM) method for estimating rates of brain changes in serial MRI from 431 subjects scanned every 6 months, for 2 years. Thompson and Holland noted an unexplained jump in our atrophy rate estimates: an offset between 0-6 months that may bias clinical trial power calculations. We identified why this jump occurs and propose a solution. By enforcing inverse-consistency in our TBM method, the offset dropped from 1.4% to 0.28%, giving plausible anatomical trajectories. Transitivity error accounted for the minimal remaining offset. Drug trial sample size estimates with the revised TBM-derived metrics are highly competitive with other methods, though higher than previously reported sample size estimates by a factor of 1.6 to 2.4. Importantly, estimates are far below those given in the critique. To demonstrate a 25% slowing of atrophic rates with 80% power, 62 AD and 129 MCI subjects would be required for a 2-year trial, and 91 AD and 192 MCI subjects for a 1-year trial. PMID:21320612

  18. A scanning measurement method of the pitch of grating based on photoelectric microscope

    NASA Astrophysics Data System (ADS)

    Gao, Hongtang; Wang, Zhongyu; Wang, Hao

    2015-10-01

    Grating is an important sensor widely used in CNC machine or equipment for length measurement with high precision. Special line scales with dense and micro lines are also widely used for the calibration of length measurement instrument. All the pitches of grating and spaces of dense lines of line scale are needed to be calibrated for a good measurement application. General methods for measurement of dense and micro lines include digital image processing method by CCD Microscope or line scanning method by AFM or SEM, and laser distraction method. There are some disadvantages to measure a long length grating with high precision and efficiently in these methods. A dynamic method based on Photoelectric Microscope is introduced, the lines of grating to be measured is moving uniformly when measuring, and the working distance is a bigger 65mm, the zoom of objective is low 10X. The principle of this dynamic method is discussed and the distortion of line signal is analyzed. The way to decrease the affection caused by distortion of line signal is also described. A special glass grating line scale with length 10mm, space 10μm and width 5μm is measured to verify the method. The measurement result and the uncertainty analysis demonstrate the expand measurement uncertainty (k=2) is less than 0.1μm.

  19. Redescription of Amblyomma varium Koch, 1844 (Acari: Ixodidae) based on light and scanning electron microscopy.

    PubMed

    Onofrio, Valeria Castilho; Barros-Battesti, Darci Moraes; Marques, Sandro; Faccini, João Luiz Horácio; Labruna, Marcelo Bahia; Beati, Lorenza; Guglielmone, Alberto Alejandro

    2008-02-01

    Amblyomma varium Koch, 1844 is a Neotropical tick, known as the 'sloth's giant tick', with records from southern Central America to Argentina. It is found almost exclusively on mammals of the families Bradypodidae and Magalonychidae (Xenarthra). Differences exist in discussions with regard to the dentition of the female hypostome being either 3/3 or 4/4. The male was also originally described as having a short spur on coxa IV, but some specimens recently collected from different Brazilian localities have this spur three times longer. These differences beg the question of whether there is more than one species included under this taxon. In order to answer this question and to clarify the taxonomic characters of this species, 258 adult specimens were examined, and a redescription of male and female based on light and scanning electron microscopy is provided. In addition, DNA was extracted from males with either a long or a short spur on coxa IV to help settle this question for future investigations on their taxonomy. The morphological study showed that the dental formula pattern for males and females is 3/3 and 4/4, respectively. When sequenced, the 12 S rDNA genes of both A. varium males with long and short spurs on coxa IV were found to be identical, indicating that the length of the spurs on coxa IV is likely to be an intraspecifically polymorphic character of this species.

  20. Design and experiment of spectrometer based on scanning micro-grating integrating with angle sensor

    NASA Astrophysics Data System (ADS)

    Biao, Luo; Wen, Zhi-yu

    2014-01-01

    A compact, low cost, high speed, non-destructive testing NIR (near infrared) spectrometer optical system based on MOEMS grating device is developed. The MOEMS grating works as the prismatic element and wavelength scanning element in our optical system. The MOEMS grating enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element. This MOEMS grating is driven by electromagnetic force and integrated with angle sensor which used to monitored deflection angle while the grating working. Comparing with the traditional spectral system, there is a new structure with a single detector and worked at high frequency. With the characteristics of MOEMS grating, the structure of the spectrometer system is proposed. After calculating the parameters of the optical path, ZEMAX optical software is used to simulate the system. According the ZEMAX output file of the 3D model, the prototype is designed by SolidWorks rapidly, fabricated. Designed for a wavelength range between 800 nm and 1500 nm, the spectrometer optical system features a spectral resolution of 16 nm with the volume of 97 mm × 81.7 mm × 81 mm. For the purpose of reduce modulated effect of sinusoidal rotation, spectral intensity of the different wavelength should be compensated by software method in the further. The system satisfies the demand of NIR micro-spectrometer with a single detector.

  1. Photoelectric scanning-based method for positioning omnidirectional automatic guided vehicle

    NASA Astrophysics Data System (ADS)

    Huang, Zhe; Yang, Linghui; Zhang, Yunzhi; Guo, Yin; Ren, Yongjie; Lin, Jiarui; Zhu, Jigui

    2016-03-01

    Automatic guided vehicle (AGV) as a kind of mobile robot has been widely used in many applications. For better adapting to the complex working environment, more and more AGVs are designed to be omnidirectional by being equipped with Mecanum wheels for increasing their flexibility and maneuverability. However, as the AGV with this kind of wheels suffers from the position errors mainly because of the frequent slipping property, how to measure its position accurately in real time is an extremely important issue. Among the ways of achieving it, the photoelectric scanning methodology based on angle measurement is efficient. Hence, we propose a feasible method to ameliorate the positioning process, which mainly integrates four photoelectric receivers and one laser transmitter. To verify the practicality and accuracy, actual experiments and computer simulations have been conducted. In the simulation, the theoretical positioning error is less than 0.28 mm in a 10 m×10 m space. In the actual experiment, the performances about the stability, accuracy, and dynamic capability of this method were inspected. It demonstrates that the system works well and the performance of the position measurement is high enough to fulfill the mainstream tasks.

  2. Three-dimensional microscope vision system based on micro laser line scanning and adaptive genetic algorithms

    NASA Astrophysics Data System (ADS)

    Apolinar, J.; Rodríguez, Muñoz

    2017-02-01

    A microscope vision system to retrieve small metallic surface via micro laser line scanning and genetic algorithms is presented. In this technique, a 36 μm laser line is projected on the metallic surface through a laser diode head, which is placed to a small distance away from the target. The micro laser line is captured by a CCD camera, which is attached to the microscope. The surface topography is computed by triangulation by means of the line position and microscope vision parameters. The calibration of the microscope vision system is carried out by an adaptive genetic algorithm based on the line position. In this algorithm, an objective function is constructed from the microscope geometry to determine the microscope vision parameters. Also, the genetic algorithm provides the search space to calculate the microscope vision parameters with high accuracy in fast form. This procedure avoids errors produced by the missing of references and physical measurements, which are employed by the traditional microscope vision systems. The contribution of the proposed system is corroborated by an evaluation via accuracy and speed of the traditional microscope vision systems, which retrieve micro-scale surface topography.

  3. Field programmable gate array based reconfigurable scanning probe/optical microscope.

    PubMed

    Nowak, Derek B; Lawrence, A J; Dzegede, Zechariah K; Hiester, Justin C; Kim, Cliff; Sánchez, Erik J

    2011-10-01

    The increasing popularity of nanometrology and nanospectroscopy has pushed researchers to develop complex new analytical systems. This paper describes the development of a platform on which to build a microscopy tool that will allow for flexibility of customization to suit research needs. The novelty of the described system lies in its versatility of capabilities. So far, one version of this microscope has allowed for successful near-field and far-field fluorescence imaging with single molecule detection sensitivity. This system is easily adapted for reflection, polarization (Kerr magneto-optical (MO)), Raman, super-resolution techniques, and other novel scanning probe imaging and spectroscopic designs. While collecting a variety of forms of optical images, the system can simultaneously monitor topographic information of a sample with an integrated tuning fork based shear force system. The instrument has the ability to image at room temperature and atmospheric pressure or under liquid. The core of the design is a field programmable gate array (FPGA) data acquisition card and a single, low cost computer to control the microscope with analog control circuitry using off-the-shelf available components. A detailed description of electronics, mechanical requirements, and software algorithms as well as examples of some different forms of the microscope developed so far are discussed.

  4. Three-dimensional measurement of femur based on structured light scanning

    NASA Astrophysics Data System (ADS)

    Li, Jie; Ouyang, Jianfei; Qu, Xinghua

    2009-12-01

    Osteometry is fundamental to study the human skeleton. It has been widely used in palaeoanthropology, bionics, and criminal investigation for more than 200 years. The traditional osteometry is a simple 1-dimensional measurement that can only get 1D size of the bones in manual step-by-step way, even though there are more than 400 parameters to be measured. For today's research and application it is significant and necessary to develop an advanced 3-dimensional osteometry technique. In this paper a new 3D osteometry is presented, which focuses on measurement of the femur, the largest tubular bone in human body. 3D measurement based on the structured light scanning is developed to create fast and precise measurement of the entire body of the femur. The cloud data and geometry model of the sample femur is established in mathematic, accurate and fast way. More than 30 parameters are measured and compared with each other. The experiment shows that the proposed method can meet traditional osteometry and obtain all 1D geometric parameters of the bone at the same time by the mathematics model, such as trochanter-lateral condyle length, superior breadth of shaft, and collo-diaphyseal angle, etc. In the best way, many important geometric parameters that are very difficult to measure by existing osteometry, such as volume, surface area, and curvature of the bone, can be obtained very easily. The overall measuring error is less than 0.1mm.

  5. Three-dimensional measurement of femur based on structured light scanning

    NASA Astrophysics Data System (ADS)

    Li, Jie; Ouyang, Jianfei; Qu, Xinghua

    2010-03-01

    Osteometry is fundamental to study the human skeleton. It has been widely used in palaeoanthropology, bionics, and criminal investigation for more than 200 years. The traditional osteometry is a simple 1-dimensional measurement that can only get 1D size of the bones in manual step-by-step way, even though there are more than 400 parameters to be measured. For today's research and application it is significant and necessary to develop an advanced 3-dimensional osteometry technique. In this paper a new 3D osteometry is presented, which focuses on measurement of the femur, the largest tubular bone in human body. 3D measurement based on the structured light scanning is developed to create fast and precise measurement of the entire body of the femur. The cloud data and geometry model of the sample femur is established in mathematic, accurate and fast way. More than 30 parameters are measured and compared with each other. The experiment shows that the proposed method can meet traditional osteometry and obtain all 1D geometric parameters of the bone at the same time by the mathematics model, such as trochanter-lateral condyle length, superior breadth of shaft, and collo-diaphyseal angle, etc. In the best way, many important geometric parameters that are very difficult to measure by existing osteometry, such as volume, surface area, and curvature of the bone, can be obtained very easily. The overall measuring error is less than 0.1mm.

  6. A basic study on variable-gain Kalman filter based on angle error calculated from acceleration signals for lower limb angle measurement with inertial sensors.

    PubMed

    Teruyama, Yuta; Watanabe, Takashi

    2013-01-01

    In this study, development of wearable motion measurement system using inertial sensors has been focused with the aim of rehabilitation support. For measurement of lower limb joint angles with inertial sensors, Kalman-filtering-based angle measurement method was developed. However, it was required to reduce variation of measurement errors that depended on movement speeds or subjects. In this report, variable-gain Kalman filter based on the difference between the estimated angle by the Kalman filter and the angle calculated from acceleration signals was tested. From angle measurement during treadmill walking with healthy subjects, it was shown that measurement accuracy of the foot inclination angle was significantly improved with the proposed method compared to the method of fixed parameter value.

  7. Earth Limb Radiance Transformation.

    DTIC Science & Technology

    1981-03-02

    AD-A097 523 AEROSPACE CORP EL SEGUNDO CA CHEMISTRY AND PHYSICS LAB F/G 4/1 EARTH LIMB RADIANCE TRANSFORMATION (U) MAR AI S 4 YOUNG F0701-80 -C-0081... Earth Limb Radiance Trafisformation Prepared by S. J. YOUNG Chemistr and Physics Laboratory Laboratory Operations The Aerospace Corporation S.El...ITLEK (and Subtitle) TYPE OF REPORT & P53100 COVERED Earth Limb Radiance Transformation. ( Interim ./ / /TR-OJ081(697j7-g4)-l-- i7.Step hen J. Young

  8. Out on a Limb: Investigating the Anatomy of Tree Limbs

    ERIC Educational Resources Information Center

    Shaw, Edward L.

    2008-01-01

    The author presents several upper elementary science activities involving tree limbs that were collected after severe weather conditions. The activities involved 3rd-grade students arranging tree limb pieces in the correct order from the trunk to the tip of the limb, measuring the pieces, determining the age of a tree limb by its rings,…

  9. A magnetorheological damper-based prosthetic knee (MRPK) and sliding mode tracking control method for an MRPK-based lower limb prosthesis

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Wang, Dai-Hua; Xu, Lei; Yuan, Gang

    2017-04-01

    Based on a two-bar linkage and a magnetorheological damper (MRD) with a double-ended structure and shearing operation mode of the magnetorheological fluid, an MRD-based prosthetic knee (MRPK) is realized. Utilizing the developed MRPK, an MRD-based lower limb prosthesis (MRLLP) is developed, modeled, and simulated in this paper, to analyse the effects of hysteresis of the integrated MRD on the swing angle of the shank of the MRLLP. Based on this, a sliding mode tracking control (SMTC) method for controlling the swing angle of the shank of the MRLLP is proposed to suppress hysteresis, along with a robustness analysis. Utilizing the SMTC method, co-simulations on controlling the swing angle of the shank of the MRLLP are carried out in ADAMS and Simulink. The simulation results show that the root mean square error (RMSE) of the swing angle of the shank of the MRLLP produced by the SMTC method is 80% less than that from the computed torque plus PD (CT+PD) control method. Therefore, the SMTC method is effective in suppressing hysteresis of the MRD. Furthermore, when the MRLLP is disturbed, the RMSE of the swing angle of the shank of the MRLLP produced by the SMTC method is 67% less than that from the CT+PD control method. Therefore, the SMTC method has strong robustness to random disturbance. A rapid control prototype of the MRLLP system and a corresponding experimental test system are established. On the established experimental test system, experiments are carried out on control of the swing angle of the shank of the MRLLP via the SMTC method. The results are compared with those from the ON/OFF and the CT+PD control methods. The experimental results show that the MRPK has controllable joint torque, and can be used to imitate the natural swing of a human knee joint. Additionally, the RMSE of the controlled swing angle of the shank of the MRLLP produced by the SMTC method is 34% less than that produced by the CT+PD control method and is 37% less than that from the ON

  10. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    SciTech Connect

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J.

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  11. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

    PubMed Central

    2011-01-01

    Background The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. Methods One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. Results Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. Conclusions A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques. PMID:22004072

  12. PTSD in Limb Trauma and Recovery

    DTIC Science & Technology

    2008-10-16

    self-report and performance-based measures; 2) To test a new scoring system for the Prosthetic Evaluation Questionnaire (PEQ); 3) To determine if...13 “ANALYSIS OF GAIT MECHANICS OF AMPUTEES USING A NEW LOWER LIMB PROSTHESIS ” CONCLUSION...of the first lower limb prosthesis with a powered, biomimetic ankle. ANNUAL REPORT 9/17/2008 VIRTUAL REALITY AND MOTION ANALYSIS TO

  13. Photodynamic therapy light dose analysis of a patient based upon arterial and venous contrast CT scan information

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Davis, Scott C.; Dehghani, Hamid; Huggett, Matthew; Hasan, Tayyaba; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to determine the light dose required to induce necrosis in verteporfin-based photodynamic therapy, in the VERTPAC-1 trial. Patient CT scans were obtained of the abdomen, including the entire treatment zone of pancreas and surrounding tissues, before and after treatment, as well as fast scans during needle placement. These scans were used to estimate arterial and venous blood content, and provide structural information of the pancreas and nearby blood vessels. Using NIRFAST, a finite-element based package for modeling diffuse near-infrared light transport in tissue, simulations were run to create maps of light fluence within the pancreas. These maps provided visualizations of light dose overlaid on the original CT scans, and were used to estimate light dose at the boundary of the zone of necrosis, as observed in follow up treatment outcome CT scans. The aim of these simulation studies was to assist pre-treatment planning by informing the light treatment parameters. This paper presents a case study of the process used on a single patient.

  14. PSIDD3: Post-Scan Ultrasonic Data Display System for the Windows-Based PC Including Fuzzy Logic Analysis

    NASA Technical Reports Server (NTRS)

    Lovelace, Jeffrey J.; Cios, Krzysztof J.; Roth, Don J.; Cao, Wei

    2000-01-01

    Post-Scan Interactive Data Display (PSIDD) III is a user-oriented Windows-based system that facilitates the display and comparison of ultrasonic contact data. The system is optimized to compare ultrasonic measurements made at different locations within a material or at different stages of material degradation. PSIDD III provides complete analysis of the primary wave forms in the time and frequency domains along with the calculation of several frequency dependent properties including Phase Velocity and Attenuation Coefficient and several frequency independent properties, like the Cross Correlation Velocity. The system allows image generation on all of the frequency dependent properties at any available frequency (limited by the bandwidth used in the scans) and on any of the frequency independent properties. From ultrasonic contact scans, areas of interest on an image can be studied with regard to underlying raw waveforms and derived ultrasonic properties by simply selecting the point on the image. The system offers various modes of in-depth comparison between scan points. Up to five scan points can be selected for comparative analysis at once. The system was developed with Borland Delphi software (Visual Pascal) and is based on a SQL database. It is ideal for classification of material properties, or location of microstructure variations in materials.

  15. Computationally Efficient Steady-State Solution of the Bloch Equations for Rapid Sinusoidal Scans Based on Fourier Expansion in Harmonics of the Scan Frequency.

    PubMed

    Tseitlin, Mark; Eaton, Gareth R; Eaton, Sandra S

    2013-12-01

    Rapid-scan EPR has been shown to improve the signal-to-noise ratio relative to conventional continuous wave spectroscopy. Equations are derived for the steady-state solution to the Bloch equations as a Fourier expansion in the harmonics of the scan frequency. This simulation method is about two orders of magnitude faster than time-domain numerical integration.

  16. Phantom limb pain

    MedlinePlus

    ... Philadelphia, PA: Elsevier; 2015:chap 54. Nikolajsen L, Springer JS, Haroutiunian S. Phantom limb pain. In: Benzon HT, ... medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- ...

  17. One of the most urgent vascular circumstances: Acute limb ischemia

    PubMed Central

    Sahin, Muslum; Kirma, Cevat

    2013-01-01

    Acute limb ischemia is a sudden decrease in limb perfusion that threatens limb viability and requires urgent evaluation and management. Most of the causes of acute limb ischemia are thrombosis of a limb artery or bypass graft, embolism from the heart or a disease artery, dissection, and trauma. Assessment determines whether the limb is viable or irreversibly damaged. Prompt diagnosis and revascularization by means of catheter-based thrombolysis or thrombectomy and by surgery reduce the risk of limb loss and mortality. Amputation is performed in patients with irreversible damage. Despite urgent revascularization, amputation rate is 10%–15% in patients during hospitalization, mostly above the knee, and mortality within 1 year is 10%–15% due to the coexisting conditions. PMID:26770694

  18. Hyaluronan in limb morphogenesis.

    PubMed

    Li, Yingcui; Toole, Bryan P; Dealy, Caroline N; Kosher, Robert A

    2007-05-15

    Hyaluronan (HA) is a large glycosaminoglycan that is not only a structural component of extracellular matrices, but also interacts with cell surface receptors to promote cell proliferation, migration, and intracellular signaling. HA is a major component of the extracellular matrix of the distal subapical mesenchymal cells of the developing limb bud that are undergoing proliferation, directed migration, and patterning in response to the apical ectodermal ridge (AER), and has the functional potential to be involved in these processes. Here we show that the HA synthase Has2 is abundantly expressed by the distal subridge mesodermal cells of the chick limb bud and also by the AER itself. Has2 expression and HA production are downregulated in the proximal central core of the limb bud during the formation of the precartilage condensations of the skeletal elements, suggesting that downregulation of HA may be necessary for the close juxtaposition of cells and the resulting cell-cell interactions that trigger cartilage differentiation during condensation. Overexpression of Has2 in the mesoderm of the chick limb bud in vivo results in the formation of shortened and severely malformed limbs that lack one or more skeletal elements. Skeletal elements that do form in limbs overexpressing Has2 are reduced in length, exhibit abnormal morphology, and are positioned inappropriately. We also demonstrate that sustained HA production in micromass cultures of limb mesenchymal cells inhibits formation of precartilage condensations and subsequent chondrogenesis, indicating that downregulation of HA is indeed necessary for formation of the precartilage condensations that trigger cartilage differentiation. Taken together these results suggest involvement of HA in various aspects of limb morphogenesis.

  19. Continuum limbed robots for locomotion

    NASA Astrophysics Data System (ADS)

    Mutlu, Alper

    This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

  20. Limb regeneration: a new development?

    PubMed

    Nacu, Eugen; Tanaka, Elly M

    2011-01-01

    Salamander limb regeneration is a classical model of tissue morphogenesis and patterning. Through recent advances in cell labeling and molecular analysis, a more precise, mechanistic understanding of this process has started to emerge. Long-standing questions include to what extent limb regeneration recapitulates the events observed in mammalian limb development and to what extent are adult- or salamander- specific aspects deployed. Historically, researchers studying limb development and limb regeneration have proposed different models of pattern formation. Here we discuss recent data on limb regeneration and limb development to argue that although patterning mechanisms are likely to be similar, cell plasticity and signaling from nerves play regeneration-specific roles.

  1. Geomorphological Mapping with Terrestrial Laser Scanning and Uav-Based Imaging

    NASA Astrophysics Data System (ADS)

    Tilly, N.; Kelterbaum, D.; Zeese, R.

    2016-06-01

    High-resolution digital elevation models (DEMs) are useful for the detailed mapping of geomorphological features. Nowadays various sensors and platforms are available to collect 3D data. The presented study compares terrestrial laser scanning (TLS) and low-cost unmanned aerial vehicles (UAV)-based imaging in terms of their usability for capturing small-scale surface structures. In October 2014 and June 2015 measurements with both systems were carried out in an episodically water-filled karst depression under pasture farming in the region of Hohenlohe (Southwest Germany). The overall aims were to establish high-resolution DEMs and monitor changes of the relief caused by dissolution and compare the advantages and drawbacks of both systems for such studies. Due to the short time between the campaigns the clear detection of temporal changes was hardly possible. However, the multi-temporal campaigns allowed an extensive investigation of the usability of both sensors under different environmental conditions. In addition to the remote sensing measurements, the coordinates of several positions in the study area were measured with a RTK-DGPS system as independent reference data sets in both campaigns. The TLS- and UAV-derived DEM heights at these positions were validated against the DGPS-derived heights. The accuracy of the TLS-derived values is supported by low mean differences between TLS and DGPS measurements while the UAV-derived models show a weaker performance. In the future years additional simultaneous measurements with both approaches under more similar vegetation conditions are necessary to detect surface movements. Moreover, by investigating the subsurface the interaction of above and below ground processes might be detected.

  2. A wire scanning based method for geometric calibration of high resolution CT system

    NASA Astrophysics Data System (ADS)

    Jiang, Ruijie; Li, Guang; Gu, Ning; Chen, Gong; Luo, Shouhua

    2015-03-01

    This paper is about geometric calibration of the high resolution CT (Computed Tomography) system. Geometric calibration refers to the estimation of a set of parameters that describe the geometry of the CT system. Such parameters are so important that a little error of them will degrade the reconstruction images seriously, so more accurate geometric parameters are needed in the higher-resolution CT systems. But conventional calibration methods are not accurate enough for the current high resolution CT system whose resolution can reach sub-micrometer or even tens of nanometers. In this paper, we propose a new calibration method which has higher accuracy and it is based on the optimization theory. The superiority of this method is that we build a new cost function which sets up a relationship between the geometrical parameters and the binary reconstruction image of a thin wire. When the geometrical parameters are accurate, the cost function reaches its maximum value. In the experiment, we scanned a thin wire as the calibration data and a thin bamboo stick as the validation data to verify the correctness of the proposed method. Comparing with the image reconstructed with the geometric parameters calculated by using the conventional calibration method, the image reconstructed with the parameters calculated by our method has less geometric artifacts, so it can verify that our method can get more accurate geometric calibration parameters. Although we calculated only one geometric parameter in this paper, the geometric artifacts are still eliminated significantly. And this method can be easily generalized to all the geometrical parameters calibration in fan-beam or cone-beam CT systems.

  3. Method for visualization and presentation of priceless old prints based on precise 3D scan

    NASA Astrophysics Data System (ADS)

    Bunsch, Eryk; Sitnik, Robert

    2014-02-01

    Graphic prints and manuscripts constitute main part of the cultural heritage objects created by the most of the known civilizations. Their presentation was always a problem due to their high sensitivity to light and changes of external conditions (temperature, humidity). Today it is possible to use an advanced digitalization techniques for documentation and visualization of mentioned objects. In the situation when presentation of the original heritage object is impossible, there is a need to develop a method allowing documentation and then presentation to the audience of all the aesthetical features of the object. During the course of the project scans of several pages of one of the most valuable books in collection of Museum of Warsaw Archdiocese were performed. The book known as "Great Dürer Trilogy" consists of three series of woodcuts by the Albrecht Dürer. The measurement system used consists of a custom designed, structured light-based, high-resolution measurement head with automated digitization system mounted on the industrial robot. This device was custom built to meet conservators' requirements, especially the lack of ultraviolet or infrared radiation emission in the direction of measured object. Documentation of one page from the book requires about 380 directional measurements which constitute about 3 billion sample points. The distance between the points in the cloud is 20 μm. Provided that the measurement with MSD (measurement sampling density) of 2500 points makes it possible to show to the publicity the spatial structure of this graphics print. An important aspect is the complexity of the software environment created for data processing, in which massive data sets can be automatically processed and visualized. Very important advantage of the software which is using directly clouds of points is the possibility to manipulate freely virtual light source.

  4. Silicon-based molecular nanotechnology: Fabrication and characterization with the scanning tunneling microscope

    NASA Astrophysics Data System (ADS)

    Hersam, Mark Christopher

    2000-10-01

    The importance of molecular nanotechnology has recently been underscored by increased media, public, and government awareness of the subject. This thesis examines several nanotechnology issues on the technologically significant Si(100) surface with the ultra-high vacuum scanning tunneling microscope (UHV-STM). Nanoscale studies have revealed that the in situ H-passivated Si(100) surface remains atomically pristine even after exposure to ambient conditions. The robustness of this surface suggests its use as a chemically inert resist layer. Using feedback-controlled lithography (FCL), individual hydrogen atoms can be removed from the Si(100)-2x1:H surface. The remaining dangling bond patterns serve as atomically precise templates upon which other materials can spontaneously self-assemble. By utilizing this selective chemistry in situ, several organic molecules (e.g., norbornadiene (NBE), copper phthalocyanine (CuPc), and C60) have been isolated. The mechanical, chemical, and electronic properties of these individual adsorbed species are then immediately detected with the STM. For CuPc, the spatial extent of charge transfer from the substrate to the adsorbate is measured as a function of binding orientation. When the CuPc is reduced with ammonia, single molecule rotation is observed. STM spectroscopic measurements on C 60 reveal intramolecular variations in the electronic density of states. For electronic applications, the application of lateral electrical fields to individual molecules is crucial. A fully compatible electrical contacting scheme based on p-n junctions will be presented. Efficient STM potentiometric location of these p-n junctions suggests their additional use as alignment markers. Beyond outlining advances in molecular nanoelectronics, this thesis will also draw connections between fundamental silicon research and current technology.

  5. Effects of varying inter-limb spacing to limb length ratio in metachronal swimming

    NASA Astrophysics Data System (ADS)

    Lai, Hong Kuan; Merkel, Rachael; Santhanakrishnan, Arvind

    2016-11-01

    Crustaceans such as shrimp, krill and crayfish swim by rhythmic paddling of four to five pairs of closely spaced limbs. Each pair is phase-shifted in time relative to the neighboring pair, resulting in a metachronal wave that travels in the direction of animal motion. The broad goal of this study is to investigate how the mechanical design of the swimming limbs affect scalability of metachronal swimming in terms of limb-based Reynolds number (Re). A scaled robotic model of metachronal paddling was developed, consisting of four pairs of hinged acrylic plates actuated using stepper motors that were immersed in a rectangular tank containing water-glycerin fluid medium. 2D PIV measurements show that the propulsive jets transition from being primarily horizontal (thrust-producing direction) at Re of order 10 to angled vertically at Re of order 100. The ratio of inter-limb spacing to limb length among metachronal swimming organisms ranges between 0.2 to 0.65. 2D PIV will be used to examine the jets generated between adjacent limbs for varying inter-limb spacing to limb length ratios. The effect of increasing this ratio to beyond the biologically observed range will be discussed.

  6. A systematic graph-based method for the kinematic synthesis of non-anthropomorphic wearable robots for the lower limbs

    NASA Astrophysics Data System (ADS)

    Sergi, Fabrizio; Accoto, Dino; Tagliamonte, Nevio L.; Carpino, Giorgio; Guglielmelli, Eugenio

    2011-03-01

    The choice of non-anthropomorphic kinematic solutions for wearable robots is motivated both by the necessity of improving the ergonomics of physical Human-Robot Interaction and by the chance of exploiting the intrinsic dynamical properties of the robotic structure so to improve its performances. Under these aspects, this new class of robotic solutions is potentially advantageous over the one of anthropomorphic robotic orthoses. However, the process of kinematic synthesis of non-anthropomorphic wearable robots can be too complex to be solved uniquely by relying on conventional synthesis methods, due to the large number of open design parameters. A systematic approach can be useful for this purpose, since it allows to obtain the complete list of independent kinematic solutions with desired properties. In this perspective, this paper presents a method, which allows to generalize the problem of kinematic synthesis of a non-anthropomorphic wearable robot for the assistance of a specified set of contiguous body segments. The methodology also includes two novel tests, specifically devised to solve the problem of enumeration of kinematic structures of wearable robots: the HR-isomorphism and the HR-degeneracy tests. This method has been implemented to derive the atlas of independent kinematic solutions suitable to be used for the kinematic design of a planar wearable robot for the lower limbs.

  7. Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.

    PubMed

    Sugisaki, Norihide; Okada, Junichi; Kanehisa, Hiroaki

    2013-01-01

    The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.

  8. Uncertainties in Recent Satellite Ozone Profile Trend Assessments (SI2N, WMO 2014): A Network-Based Assessment of Fourteen Contributing Limb and Occultation Data Records

    NASA Astrophysics Data System (ADS)

    Hubert, D.; Lambert, J.-C.; Verhoelst, T.; Granville, J.; Keppens, A.; Cortesi, U.; Degenstein, D. A.; Froidevaux, L.; Godin-Beekmann, S.; Hoppel, K. W.; Kyrola, E.; Leblanc, T.; Lichtenberg, G.; McDermid, I. S.; McElroy, C. T.; Murtagh, D.; Nakane, H.; Russell, J. M., III; Smit, H. G. J.; Stebel, K.; Steinbrecht, W.; Stubi, R.; Swart, D. P. J.; Taha, G.; Thompson, A. M.; Urban, J.; van Gijsel, J. A. E.; von der Gathen, P.; Walker, K. A.; Zawodny, J. M.

    2015-11-01

    Numerous vertical ozone profile data records collected over the past decades from space-based platforms have the potential to allow the ozone and climate communities to tackle a variety of research questions. A prime topic is the study and documentation of long-term changes in the vertical distribution of atmospheric ozone, as targeted by the recent SPARC/IO3C/IGACO- O3/NDACC Initiative (SI2N) and WMO's ozone assessment. Such studies typically require data records with documented mutual consistency in terms of bias and long-term stability. We performed a comprehensive assessment of fourteen limb/occultation ozone profile data records, using NDACC/GAW/SHADOZ ozonesonde and NDACC lidar network data as reference standards.

  9. A quantitative damage imaging technique based on enhanced CCRTM for composite plates using 2D scan

    NASA Astrophysics Data System (ADS)

    He, Jiaze; Yuan, Fuh-Gwo

    2016-10-01

    A two-dimensional (2D) non-contact areal scan system was developed to image and quantify impact damage in a composite plate using an enhanced zero-lag cross-correlation reverse-time migration (E-CCRTM) technique. The system comprises a single piezoelectric wafer mounted on the composite plate and a laser Doppler vibrometer (LDV) for scanning a region in the vicinity of the PZT to capture the scattered wavefield. The proposed damage imaging technique takes into account the amplitude, phase, geometric spreading, and all of the frequency content of the Lamb waves propagating in the plate; thus, a reflectivity coefficients of the delamination is calculated and potentially related to damage severity. Comparisons are made in terms of damage imaging quality between 2D areal scans and 1D line scans as well as between the proposed and existing imaging conditions. The experimental results show that the 2D E-CCRTM performs robustly when imaging and quantifying impact damage in large-scale composites using a single PZT actuator with a nearby areal scan using LDV.

  10. Aerosol Plume Detection Algorithm Based on Image Segmentation of Scanning Atmospheric Lidar Data

    SciTech Connect

    Weekley, R. Andrew; Goodrich, R. Kent; Cornman, Larry B.

    2016-04-01

    An image-processing algorithm has been developed to identify aerosol plumes in scanning lidar backscatter data. The images in this case consist of lidar data in a polar coordinate system. Each full lidar scan is taken as a fixed image in time, and sequences of such scans are considered functions of time. The data are analyzed in both the original backscatter polar coordinate system and a lagged coordinate system. The lagged coordinate system is a scatterplot of two datasets, such as subregions taken from the same lidar scan (spatial delay), or two sequential scans in time (time delay). The lagged coordinate system processing allows for finding and classifying clusters of data. The classification step is important in determining which clusters are valid aerosol plumes and which are from artifacts such as noise, hard targets, or background fields. These cluster classification techniques have skill since both local and global properties are used. Furthermore, more information is available since both the original data and the lag data are used. Performance statistics are presented for a limited set of data processed by the algorithm, where results from the algorithm were compared to subjective truth data identified by a human.

  11. Aerosol Plume Detection Algorithm Based on Image Segmentation of Scanning Atmospheric Lidar Data

    DOE PAGES

    Weekley, R. Andrew; Goodrich, R. Kent; Cornman, Larry B.

    2016-04-06

    An image-processing algorithm has been developed to identify aerosol plumes in scanning lidar backscatter data. The images in this case consist of lidar data in a polar coordinate system. Each full lidar scan is taken as a fixed image in time, and sequences of such scans are considered functions of time. The data are analyzed in both the original backscatter polar coordinate system and a lagged coordinate system. The lagged coordinate system is a scatterplot of two datasets, such as subregions taken from the same lidar scan (spatial delay), or two sequential scans in time (time delay). The lagged coordinatemore » system processing allows for finding and classifying clusters of data. The classification step is important in determining which clusters are valid aerosol plumes and which are from artifacts such as noise, hard targets, or background fields. These cluster classification techniques have skill since both local and global properties are used. Furthermore, more information is available since both the original data and the lag data are used. Performance statistics are presented for a limited set of data processed by the algorithm, where results from the algorithm were compared to subjective truth data identified by a human.« less

  12. Aerosol Plume Detection Algorithm Based on Image Segmentation of Scanning Atmospheric Lidar Data

    SciTech Connect

    Weekley, R. Andrew; Goodrich, R. Kent; Cornman, Larry B.

    2016-04-06

    An image-processing algorithm has been developed to identify aerosol plumes in scanning lidar backscatter data. The images in this case consist of lidar data in a polar coordinate system. Each full lidar scan is taken as a fixed image in time, and sequences of such scans are considered functions of time. The data are analyzed in both the original backscatter polar coordinate system and a lagged coordinate system. The lagged coordinate system is a scatterplot of two datasets, such as subregions taken from the same lidar scan (spatial delay), or two sequential scans in time (time delay). The lagged coordinate system processing allows for finding and classifying clusters of data. The classification step is important in determining which clusters are valid aerosol plumes and which are from artifacts such as noise, hard targets, or background fields. These cluster classification techniques have skill since both local and global properties are used. Furthermore, more information is available since both the original data and the lag data are used. Performance statistics are presented for a limited set of data processed by the algorithm, where results from the algorithm were compared to subjective truth data identified by a human.

  13. Development of limb volume measuring system

    NASA Technical Reports Server (NTRS)

    Bhagat, P. K.; Kadaba, P. K.

    1983-01-01

    The mechanisms underlying the reductions in orthostatic tolerance associated with weightlessness are not well established. Contradictory results from measurements of leg volume changes suggest that altered venomotor tone and reduced blood flow may not be the only contributors to orthostatic intolerance. It is felt that a more accurate limb volume system which is insensitive to environmental factors will aid in better quantification of the hemodynamics of the leg. Of the varous limb volume techniques presently available, the ultrasonic limb volume system has proven to be the best choice. The system as described herein is free from environmental effects, safe, simple to operate and causes negligible radio frequency interference problems. The segmental ultrasonic ultrasonic plethysmograph is expected to provide a better measurement of limb volume change since it is based on cross-sectional area measurements.

  14. Airborne Laser Scanning - based vegetation classification in grasslands: a feasibility study

    NASA Astrophysics Data System (ADS)

    Zlinszky, András; Vári, Ágnes; Deák, Balázs; Mücke, Werner; Székely, Balázs

    2013-04-01

    Airborne Laser Scanning is traditionally used for topography mapping, exploiting its ability to map terrain elevation under vegetation cover. Parallel to this, the application of ALS for vegetation classification and mapping of ecological variables is rapidly emerging. Point clouds surveyed by ALS provide accurate representations of vegetation structure and are therefore considered suitable for mapping vegetation classes as long as their vertical structure is characteristic. For this reason, most ALS-based vegetation mapping studies have been carried out in forests, with some rare applications for shrublands or tall grass vegetation such as reeds. The use of remote-sensing derived vegetation maps is widespread in ecological research and is also gaining importance in practical conservation. There is an increasing demand for reliable, high-resolution datasets covering large protected areas. ALS can provide both the coverage and the high resolution, and can prove to be an economical solution due to the potential for automatic processing and the wide range of uses that allows spreading costs. Grasslands have a high importance in nature conservation as due to the drastical land use changes (arable lands, afforestation, fragmentation by linear structures) in the last centuries the extent of these habitats have been considerably reduced. Among the habitat types protected by the Habitat Directive of the Natura 2000 system, several grassland habitat types (e.g. hay meadows, dry grasslands harbouring rare Orchid species) have special priority for conservation. For preserving these habitat types application of a proper management - including mowing or grazing - has a crucial role. Therefore not only the mapping of the locations of habitats but the way of management is needed for representing the natural processes. The objective of this study was to test the applicability of airborne laser scanning for ecological vegetation mapping in and around grasslands. The study site is

  15. Line-scanning confocal microscopy for high-resolution imaging of upconverting rare-earth-based contrast agents

    NASA Astrophysics Data System (ADS)

    Higgins, Laura M.; Zevon, Margot; Ganapathy, Vidya; Sheng, Yang; Tan, Mei Chee; Riman, Richard E.; Roth, Charles M.; Moghe, Prabhas V.; Pierce, Mark C.

    2015-11-01

    Rare-earth (RE) doped nanocomposites emit visible luminescence when illuminated with continuous wave near-infrared light, making them appealing candidates for use as contrast agents in biomedical imaging. However, the emission lifetime of these materials is much longer than the pixel dwell times used in scanning intravital microscopy. To overcome this limitation, we have developed a line-scanning confocal microscope for high-resolution, optically sectioned imaging of samples labeled with RE-based nanomaterials. Instrument performance is quantified using calibrated test objects. NaYF4:Er,Yb nanocomposites are imaged in vitro, and in ex vivo tissue specimens, with direct comparison to point-scanning confocal microscopy. We demonstrate that the extended pixel dwell time of line-scanning confocal microscopy enables subcellular-level imaging of these nanomaterials while maintaining optical sectioning. The line-scanning approach thus enables microscopic imaging of this emerging class of contrast agents for preclinical studies, with the potential to be adapted for real-time in vivo imaging in the clinic.

  16. A new centering method of the measuring probe for spiral scanning-based surface profile measurement systems

    NASA Astrophysics Data System (ADS)

    Du, Hui-Lin; Zeng, Pei-Yang; Ju, Bing-Feng; Zhou, Zhao-Zhong; Xu, Shaoning; Sun, Anyu

    2017-02-01

    Spiral scanning is a high-efficiency scanning mode for surface profile measurement systems. The most important priority to realize the spiral scanning mode is to accurately align the measuring probe with the rotational centre of the spindle. This paper proposes a novel centre alignment method of the measuring probe, which is considered to be suitable for any type of spiral scanning surface measurement systems. The proposed method, which only needs a tilted flat mirror as the artefact, makes the time-consuming centre alignment process of the measuring probe become much easier and faster. The operational steps of the proposed method are presented. Experiments have also been carried out based on a self-developed optical profiler with spiral scanning operation to verity the feasibility of the proposed method. The experimental results show that the proposed method is capable of conducting a fast alignment (only takes 3 min) while maintaining a high alignment accuracy. Evaluation of the alignment accuracy shows that the centering error is less than 10 µm on the mechanical guide rail stage and about 1.7 µm on the air-bearing stage.

  17. Line-scanning confocal microscopy for high-resolution imaging of upconverting rare-earth-based contrast agents

    PubMed Central

    Higgins, Laura M.; Zevon, Margot; Ganapathy, Vidya; Sheng, Yang; Tan, Mei Chee; Riman, Richard E.; Roth, Charles M.; Moghe, Prabhas V.; Pierce, Mark C.

    2015-01-01

    Abstract. Rare-earth (RE) doped nanocomposites emit visible luminescence when illuminated with continuous wave near-infrared light, making them appealing candidates for use as contrast agents in biomedical imaging. However, the emission lifetime of these materials is much longer than the pixel dwell times used in scanning intravital microscopy. To overcome this limitation, we have developed a line-scanning confocal microscope for high-resolution, optically sectioned imaging of samples labeled with RE-based nanomaterials. Instrument performance is quantified using calibrated test objects. NaYF4:Er,Yb nanocomposites are imaged in vitro, and in ex vivo tissue specimens, with direct comparison to point-scanning confocal microscopy. We demonstrate that the extended pixel dwell time of line-scanning confocal microscopy enables subcellular-level imaging of these nanomaterials while maintaining optical sectioning. The line-scanning approach thus enables microscopic imaging of this emerging class of contrast agents for preclinical studies, with the potential to be adapted for real-time in vivo imaging in the clinic. PMID:26603495

  18. Top-level design and pilot analysis of low-end CT scanners based on linear scanning for developing countries.

    PubMed

    Liu, Fenglin; Yu, Hengyong; Cong, Wenxiang; Wang, Ge

    2014-01-01

    The goal is to develop new architectures for computed tomography (CT) which are at an ultra-low-cost for developing countries, especially in rural areas. The proposed general scheme is inspired by the recently developed compressive sensing and interior tomography techniques, where the data acquisition system targets a region of interest (ROI) to acquire limited and truncated data. Similar to linear tomosynthesis, the source and detector are translated in opposite directions but in contrast to conventional tomosynthesis, our proposal is for either ROI reconstruction with one or more localized linear scans or global reconstruction by combining multiple ROI reconstructions. In other words, the popular slip ring is replaced by a translation based setup, and the instrumentation cost is reduced by a relaxation of the imaging speed requirement. The various translational scanning modes are theoretically analyzed, and the scanning parameters are optimized. The numerical simulation results from different numbers of linear scans confirm the feasibility of the proposed scheme, and suggest two preferred low-end systems for horizontal and vertical patient positions respectively. Ultra-low-cost x-ray CT is feasible with our proposed combination of linear scanning, compressive sensing, and interior tomography. The proposed architecture can be tailored into permanent, movable, or reconfigurable systems as desirable. Advanced image registration and spectral imaging features can be included as well.

  19. Three-dimensional image cytometer based on a high-speed two-photon scanning microscope

    NASA Astrophysics Data System (ADS)

    Kim, Ki H.; Stitt, Molly S.; Hendricks, Carrie A.; Almeida, Karen H.; Engelward, Bevin P.; So, Peter T. C.

    2001-04-01

    We developed a 3-D image cytometer based on two-photon scanning microscopy. The system keeps the inherent advantages from two-photon scanning microscopy: (1) The ability of imaging thick tissue samples up to a few hundred micrometers, (2) The ability to study tissue structures with subcellular resolution, (3) The ability to monitor tissue biochemistry and metabolism, and (4) The reduction of specimen photobleaching and photodamage. Therefore, 3-D image cytometer has the ability to characterize multiple cell layer specimens, in contrast with 2-D image cytometer where only single cell layer samples can be imaged. 3-D image cytometry increases its frame rate by adapting a polygonal mirror scanner and high-speed photomultiplier tubes. The current frame rate is 13 frames per second. High throughput rate is achieved by imaging multiple cell layer specimens in 3-D at a high frame rate. The throughput rate of this system is dependent on the choice of objective lenses, specimen properties, and the speed of computer-controlled specimen stage. It can be up to approximately 100 cells per second which is comparable with that of 2-D image cytometers. With the high throughput rate and deep tissue imaging capability, 3-D image cytometer has the potential for the detection of rare cellular events inside living, intact tissues. A promising application of this 3-D image cytometer is the study of mitotic recombination in tissues. Mitotic recombination is a mechanism for genetic change. Therefore it is one of causes for carcinogenesis. However, the study of this process is difficult because recombination event is rare and it occurs at a rate of one cell in 105 cells. The new method for the study is (1) to engineer transgenic mice whose cells will express fluorescence in the presence of mitotic recombination, (2) to detect cells which have undergone mitotic recombination with 3-D image cytometry. The estimated time required to quantify spontaneous recombination rate is approximately

  20. Pulmonary nodule registration in serial CT scans based on rib anatomy and nodule template matching

    PubMed Central

    Shi, Jiazheng; Sahiner, Berkman; Chan, Heang-Ping; Hadjiiski, Lubomir; Zhou, Chuan; Cascade, Philip N.; Bogot, Naama; Kazerooni, Ella A.; Wu, Yi-Ta; Wei, Jun

    2009-01-01

    An automated method is being developed in order to identify corresponding nodules in serial thoracic CT scans for interval change analysis. The method uses the rib centerlines as the reference for initial nodule registration. A spatially adaptive rib segmentation method first locates the regions where the ribs join the spine, which define the starting locations for rib tracking. Each rib is tracked and locally segmented by expectation-maximization. The ribs are automatically labeled, and the centerlines are estimated using skeletonization. For a given nodule in the source scan, the closest three ribs are identified. A three-dimensional (3D) rigid affine transformation guided by simplex optimization aligns the centerlines of each of the three rib pairs in the source and target CT volumes. Automatically defined control points along the centerlines of the three ribs in the source scan and the registered ribs in the target scan are used to guide an initial registration using a second 3D rigid affine transformation. A search volume of interest (VOI) is then located in the target scan. Nodule candidate locations within the search VOI are identified as regions with high Hessian responses. The initial registration is refined by searching for the maximum cross-correlation between the nodule template from the source scan and the candidate locations. The method was evaluated on 48 CT scans from 20 patients. Experienced radiologists identified 101 pairs of corresponding nodules. Three metrics were used for performance evaluation. The first metric was the Euclidean distance between the nodule centers identified by the radiologist and the computer registration, the second metric was a volume overlap measure between the nodule VOIs identified by the radiologist and the computer registration, and the third metric was the hit rate, which measures the fraction of nodules whose centroid computed by the computer registration in the target scan falls within the VOI identified by the

  1. Extraction of the Brain from CT Head Scans Based on Domain Knowledge

    SciTech Connect

    Qian Guoyu; Luo Suhuai; Jin, Jesse; Park, Mira; Nowinski, Wieslaw L.

    2007-11-02

    We present an automatic approach for an efficient brain extraction from CT head scans. Regions of interest are first set in each slice by applying thresholding and region growing. Next, the brain candidates are extracted by using three-dimensional region growing with a variable, anatomy-dependent structuring element. Domain knowledge, including Hounsfield unit ranges, anatomy, and image acquisition parameters, is applied. The proposed method has been applied automatically to 27 CT normal and pathological scans and has shown promising results. The average sensitivity, specificity and Dice's index for 5 cases are 99.6%, 99.4% and 98.7%, respectively.

  2. [Lower limb edema and steatorrhea: value of scintigraphic technics].

    PubMed

    Bourgeois, P; Munck, D; Leduc, O

    2003-04-01

    The authors report the case of a young woman with right lower limb edema who also presented one steatorrhea. Her clinical history is typical for one primary lymphedema and the lymphoscintigraphic investigation of the lower limbs confirms the diagnosis. The scan showed the absence of the right iliac and lomboaortic lymph nodes but also that the thoracic duct was normally present. One C14-triolein breath test is pathological and proves the malabsorption of the fats. The authors discuss the interest of the scintigraphic techniques in such case and review the problem of the association between lower limb lymphedemas and fatty malabsorption.

  3. Biological sample evaluation using a line-scan based SWIR hyperspectral imaging system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new line-scan hyperspectral imaging system was developed to enable short wavelength infrared (SWIR) imagery for biological sample evaluation. Critical sensing components include a SWIR imaging spectrograph and an HgCdTe (MCT) focal plane array detector. To date, agricultural applications of infra...

  4. Cross-ratio-based line scan camera calibration using a planar pattern

    NASA Astrophysics Data System (ADS)

    Li, Dongdong; Wen, Gongjian; Qiu, Shaohua

    2016-01-01

    A flexible new technique is proposed to calibrate the geometric model of line scan cameras. In this technique, the line scan camera is rigidly coupled to a calibrated frame camera to establish a pair of stereo cameras. The linear displacements and rotation angles between the two cameras are fixed but unknown. This technique only requires the pair of stereo cameras to observe a specially designed planar pattern shown at a few (at least two) different orientations. At each orientation, a stereo pair is obtained including a linear array image and a frame image. Radial distortion of the line scan camera is modeled. The calibration scheme includes two stages. First, point correspondences are established from the pattern geometry and the projective invariance of cross-ratio. Second, with a two-step calibration procedure, the intrinsic parameters of the line scan camera are recovered from several stereo pairs together with the rigid transform parameters between the pair of stereo cameras. Both computer simulation and real data experiments are conducted to test the precision and robustness of the calibration algorithm, and very good calibration results have been obtained. Compared with classical techniques which use three-dimensional calibration objects or controllable moving platforms, our technique is affordable and flexible in close-range photogrammetric applications.

  5. B-scan based acoustic source reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI).

    PubMed

    Mariappan, Leo; Li, Xu; He, Bin

    2011-03-01

    We present in this study, an acoustic source reconstruction method using focused transducer with B-mode imaging for magnetoacoustic tomography with magnetic induction (MAT-MI). MAT-MI is an imaging modality proposed for noninvasive conductivity imaging with high spatial resolution. In MAT-MI, acoustic sources are generated in a conductive object by placing it in a static and a time-varying magnetic field. The acoustic waves from these sources propagate in all directions and are collected with transducers placed around the object. The collected signal is then used to reconstruct the acoustic source distribution and to further estimate the electrical conductivity distribution of the object. A flat piston transducer acting as a point receiver has been used in earlier MAT-MI systems to collect acoustic signals. In this study, we propose to use B-mode scan scheme with a focused transducer that gives a signal gain in its focus region and improves the MAT-MI signal quality. A simulation protocol that can take into account different transducer designs and scan schemes for MAT-MI imaging is developed and used in our evaluation of different MAT-MI system designs. It is shown in our computer simulations that as compared to the earlier approach, the MAT-MI system using B-scan with a focused transducer allows MAT-MI imaging at a closer distance and has improved system sensitivity. In addition, the B-scan imaging technique allows reconstruction of the MAT-MI acoustic sources with a discrete number of scanning locations, which greatly increases the applicability of the MAT-MI approach, especially when a continuous acoustic window is not available in real clinical applications. We have also conducted phantom experiments to evaluate the proposed method, and the reconstructed image shows a good agreement with the target phantom.

  6. Bone Scan

    MedlinePlus

    ... Mayo Clinic Staff A bone scan is a nuclear imaging test that helps diagnose and track several ... you're nursing. A bone scan is a nuclear imaging procedure. In nuclear imaging, tiny amounts of ...

  7. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  8. CRISM Limb Observations of Aerosols and Water Vapor

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Wolff, M.J.; Clancy, R.T.; Seelos, F.; Murchie, S.L.

    2009-01-01

    Near-infrared spectra taken in a limb-viewing geometry by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the Mars Reconnaissance Orbiter (MRO) provide a useful tool for probing atmospheric structure. Here we describe preliminary work on the retrieval of vertical profiles of aerosols and water vapor from the CRISM limb observations. The first full set of CRISM limb observations was taken in July 2009, with subsequent limb observations planned once every two months. Each set of limb observations contains about four dozen scans across the limb giving pole-to-pole coverage for two orbits at roughly 100 and 290 W longitude. Radiative transfer modeling taking account of aerosol scattering in the limb-viewing geometry is used to model the observations. The retrievals show the height to which dust and water vapor extend and the location and height of water ice clouds. Results from the First set of CRISM limb observations (July 2009, Ls=300) show dust aerosol well-mixed to about three scale heights above the surface with thin water ice clouds above the dust near the equator and at mid-northern latitudes. Water vapor is concentrated at high southern latitudes.

  9. Primary Upper Limb Lymphedema: Case Report of a Rare Pathology

    PubMed Central

    McFarlane, Michael EC

    2017-01-01

    Introduction Lymphedema is characterized by a defect in the lymphatic system that causes limb swelling. Impaired uptake and transport of lymphatic fluid through lymphatic vessels causes accumulation of protein-rich fluid in the interstitial spaces, which leads to swelling of the limb. Primary lymphedema often presents at birth. The rare cases that arise after age 35 years are described as lymphedema tarda. The great majority of patients with lymphedema have swelling of the lower limbs—upper limb lymphedema is a rare disorder. Case Presentation An 84-year-old woman presented with a 3-year history of unilateral swelling of the right upper limb. There were no constitutional symptoms and no evidence of lymphadenopathy or systemic disease. Blood tests, carcinoembryonic antigen test, computed tomography scans, and venous Doppler ultrasound were all normal. The diagnosis was primary upper limb lymphedema. Discussion The swelling that occurs in upper limb lymphedema is permanent and usually extends to the hand. About one-third of patients with this condition also present with lower limb lymphedema. Thorough investigations are warranted in cases of unilateral upper limb lymphedema to rule out occult malignancy and systemic disease. PMID:28080951

  10. [Optimization of policy aimed at forming a permanent access based on ultrasonographic duplex scanning for programmed dialysis].

    PubMed

    Fokin, A A; Baryshnikov, A A; Vladimirskiĭ, V V; Gasnikov, A V

    2013-01-01

    The study was aimed at optimizing the policy of forming a permanent vascular access (PVA) by means of preoperative colour duplex scanning (CDS) of vessels in patients on programmed haemodialysis. The study included 420 patients undergoing from September 2003 to September 2011 a total of 595 PVAs. The Study Group (Group I) patients (351 PVAs) were subjected to preoperative PVA of vessels of limbs accompanied by assessing velocity parameters of the venous blood flow. The comparison group (Group II) patients (244 PVAs) underwent clinical examination only. The end point of the study was early diagnosis of incompetence of the PVA. Using preoperative PVA of vessels improved the outcomes of forming the PVA, significantly increasing the number of native arteriovenous fistulas (AVF) as a whole: (88.0% for Group I and 65.6% for Group II; p<0.01), their variants: radial-cephalic (I - 57.5%, II - 32.2%; p<0.01) and secondary radial-cephalic variants (I - 8.3%, II - 3.7%; p<0.01), leading to decreased frequency of using synthetic prostheses both totally (I - 12.0%, II - 34.4%; p<0.01) and in all positions (p<0.01) taken apart. Also decreased the frequency of the development of incompetence of all PVAs (I - 10.8%, II - 29.9%; p<0.01), AVFs as a whole (I - 7.4%, II - 18.0%; p<0.01) and accesses with a synthetic prosthesis both as a whole (I - 1.7%, II - 11.9%; p<0.01) and in all positions separately (p<0.01). Determining the velocity parameters of venous blood flow made it possible to exclude the development of significant proximal venous obstruction and to refuse phlebography. We consider it obligatory to perform CDS of vessels prior to forming a PVA.

  11. The making of differences between fins and limbs

    PubMed Central

    Yano, Tohru; Tamura, Koji

    2013-01-01

    ‘Evo-devo’, an interdisciplinary field based on developmental biology, includes studies on the evolutionary processes leading to organ morphologies and functions. One fascinating theme in evo-devo is how fish fins evolved into tetrapod limbs. Studies by many scientists, including geneticists, mathematical biologists, and paleontologists, have led to the idea that fins and limbs are homologous organs; now it is the job of developmental biologists to integrate these data into a reliable scenario for the mechanism of fin-to-limb evolution. Here, we describe the fin-to-limb transition based on key recent developmental studies from various research fields that describe mechanisms that may underlie the development of fins, limb-like fins, and limbs. PMID:23256837

  12. Method for estimating errors for radiation budget based on a scanning radiometer

    NASA Technical Reports Server (NTRS)

    Smith, G. L.; Avis, L. M.; Green, R. N.; Wielicki, B. A.

    1984-01-01

    The conduction of the Earth Radiation Budget Experiment (ERBE) will involve the utilization of three sets of instruments. Each set consists of a nonscanning package and a scanning radiometer. The instruments will fly on the NOAA F and G operational satellites and on a dedicated spacecraft, the Earth Radiation Budget Satellite (ERBS). The ERBS will be in a 57 deg inclination orbit and will precess around the earth to provide sampling of the diurnal cycle of regions between + or - 57 deg latitude. The primary function of the scanning radiometer is to provide measurements for the calculation of the earth-emitted and absorbed solar radiation at the top of the earth-atmosphere system, averaged over 250 x 250 km regions. The present paper is concerned with errors found in these regional averages. Attention is given to details regarding the problem, scene identification probabilities, scene identification error effects, total pixel error, and errors due to regional averaging.

  13. Coarse-fine vertical scanning based optical profiler for structured surface measurement with large step height

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Liu, Xiaojun; Lei, Zili; Li, Qian; Yang, Xiao; Chen, Liangzhou; Lu, Wenlong

    2015-02-01

    White light interference (WLI) optical profiler had been used widely for structured surface measurement. To achieve high measuring accuracy, piezoelectric ceramic (PZT) was usually used as the vertical scanning unit, which was normally less than 100um and only for small range structured surface measurement. With the development of advanced manufacturing technology, precision structured surfaces with large step height were appearing. To satisfy the measurement requirements of this kind of precision structured surfaces, WLI optical profiler with large range had to be developed. In this paper, an optical profiler was proposed, in which a coarse-fine vertical scanning system was adopted to expand its measurement range to 10mm while its resolution still at nanometer level.

  14. Tetrahedron-based orthogonal simultaneous scan for cone-beam computed tomography.

    PubMed

    Ye, Ivan B; Wang, Ge

    2012-08-06

    In this article, a cone-beam computed tomography scanning mode is designed using four x-ray sources and a spherical sample. The x-ray sources are mounted at the vertices of a regular tetrahedron. On the circumsphere of the tetrahedron, four detection panels are mounted opposite of each vertex. To avoid x-ray interference, the largest half angle of each x-ray cone beam is 27°22', while the radius of the largest ball fully covered by all the cone beams is 0.460, when the radius of the circumsphere is 1. A proposed scanning scheme consists of two rotations about orthogonal axes, such that, each quarter turn provides sufficient data for theoretically exact and stable reconstruction. This design can be used in biomedical or industrial settings, such as when a sequence of reconstructions of an object is desired.

  15. Aberration analysis based on pinhole-z-scan method near the focal point of refractive systems

    NASA Astrophysics Data System (ADS)

    Castro-Marín, Pablo; Garduño-Mejía, Jesús; Rosete-Aguilar, Martha; Bruce, Neil C.; Reid, Derryck T.; Farrell, C.; Sandoval-Romero, Gabriel E.

    2016-09-01

    In this work we present a method used to study the spherical and chromatic aberrations contribution near the focal point of a refractive optical system. The actual focal position is measured by scanning a pinhole attached on the front of a power detector, which are scanned along the optical axis using a motorized stage with 1 μm resolution. Spherical aberration contribution was analyzed by changing the pupil aperture, by modifying the size of the input iris diaphragm and for each case, measuring the actual laser power vs the detector position. Chromatic aberration was analyzed by performing the same procedure but in this case we used an ultra-broad-band femtosecond laser. The results between ML and CW operation were compare. Experimental results are presented.

  16. Study of 3D remote sensing system based on optical scanning holography

    NASA Astrophysics Data System (ADS)

    Zhao, Shihu; Yan, Lei

    2009-06-01

    High-precision and real-time remote sensing imaging system is an important part of remote sensing development. Holography is a method of wave front record and recovery which was presented by Dennis Gabor. As a new kind of holography techniques, Optical scanning holography (OSH) and remote sensing imaging are intended to be combined together and applied in acquisition and interference measurement of remote sensing. The key principles and applicability of OSH are studied and the mathematic relation between Fresnel Zone Plate number, numerical aperture and object distance was deduced, which are proved to be feasible for OSH to apply in large scale remote sensing. At last, a new three-dimensional reflected OSH remote sensing imaging system is designed with the combination of scanning technique to record hologram patterns of large scale remote sensing scenes. This scheme is helpful for expanding OSH technique to remote sensing in future.

  17. MTR-Fill: A Simulated Annealing-Based X-Filling Technique to Reduce Test Power Dissipation for scan-Based Designs

    NASA Astrophysics Data System (ADS)

    Song, Dong-Sup; Ahn, Jin-Ho; Kim, Tae-Jin; Kang, Sungho

    This paper proposes the minimum transition random X-filling (MTR-fill) technique, which is a new X-filling method, to reduce the amount of power dissipation during scan-based testing. In order to model the amount of power dissipated during scan load/unload cycles, the total weighted transition metric (TWTM) is introduced, which is calculated by the sum of the weighted transitions in a scan-load of a test pattern and a scan-unload of a test response. The proposed MTR-fill is implemented by simulated annealing method. During the annealing process, the TWTM of a pair of test patterns and test responses are minimized. Simultaneously, the MTR-fill attempts to increase the randomness of test patterns in order to reduce the number of test patterns needed to achieve adequate fault coverage. The effectiveness of the proposed technique is shown through experiments for ISCAS' 89 benchmark circuits.

  18. A pipette-based calibration system for fast-scan cyclic voltammetry with fast response times.

    PubMed

    Ramsson, Eric S

    2016-01-01

    Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that utilizes the oxidation and/or reduction of an analyte of interest to infer rapid changes in concentrations. In order to calibrate the resulting oxidative or reductive current, known concentrations of an analyte must be introduced under controlled settings. Here, I describe a simple and cost-effective method, using a Petri dish and pipettes, for the calibration of carbon fiber microelectrodes (CFMs) using FSCV.

  19. Limb salvage surgery

    PubMed Central

    Kadam, Dinesh

    2013-01-01

    The threat of lower limb loss is seen commonly in severe crush injury, cancer ablation, diabetes, peripheral vascular disease and neuropathy. The primary goal of limb salvage is to restore and maintain stability and ambulation. Reconstructive strategies differ in each condition such as: Meticulous debridement and early coverage in trauma, replacing lost functional units in cancer ablation, improving vascularity in ischaemic leg and providing stable walking surface for trophic ulcer. The decision to salvage the critically injured limb is multifactorial and should be individualised along with laid down definitive indications. Early cover remains the standard of care, delayed wound coverage not necessarily affect the final outcome. Limb salvage is more cost-effective than amputations in a long run. Limb salvage is the choice of procedure over amputation in 95% of limb sarcoma without affecting the survival. Compound flaps with different tissue components, skeletal reconstruction; tendon transfer/reconstruction helps to restore function. Adjuvant radiation alters tissue characters and calls for modification in reconstructive plan. Neuropathic ulcers are wide and deep often complicated by osteomyelitis. Free flap reconstruction aids in faster healing and provides superior surface for offloading. Diabetic wounds are primarily due to neuropathy and leads to six-fold increase in ulcerations. Control of infections, aggressive debridement and vascular cover are the mainstay of management. Endovascular procedures are gaining importance and have reduced extent of surgery and increased amputation free survival period. Though the standard approach remains utilising best option in the reconstruction ladder, the recent trend shows running down the ladder of reconstruction with newer reliable local flaps and negative wound pressure therapy. PMID:24501463

  20. Laser cutting of irregular shape object based on stereo vision laser galvanometric scanning system

    NASA Astrophysics Data System (ADS)

    Qi, Li; Zhang, Yixin; Wang, Shun; Tang, Zhiqiang; Yang, Huan; Zhang, Xuping

    2015-05-01

    Irregular shape objects with different 3-dimensional (3D) appearances are difficult to be shaped into customized uniform pattern by current laser machining approaches. A laser galvanometric scanning system (LGS) could be a potential candidate since it can easily achieve path-adjustable laser shaping. However, without knowing the actual 3D topography of the object, the processing result may still suffer from 3D shape distortion. It is desirable to have a versatile auxiliary tool that is capable of generating 3D-adjusted laser processing path by measuring the 3D geometry of those irregular shape objects. This paper proposed the stereo vision laser galvanometric scanning system (SLGS), which takes the advantages of both the stereo vision solution and conventional LGS system. The 3D geometry of the object obtained by the stereo cameras is used to guide the scanning galvanometers for 3D-shape-adjusted laser processing. In order to achieve precise visual-servoed laser fabrication, these two independent components are integrated through a system calibration method using plastic thin film target. The flexibility of SLGS has been experimentally demonstrated by cutting duck feathers for badminton shuttle manufacture.

  1. Challenges of microtome-based serial block-face scanning electron microscopy in neuroscience.

    PubMed

    Wanner, A A; Kirschmann, M A; Genoud, C

    2015-08-01

    Serial block-face scanning electron microscopy (SBEM) is becoming increasingly popular for a wide range of applications in many disciplines from biology to material sciences. This review focuses on applications for circuit reconstruction in neuroscience, which is one of the major driving forces advancing SBEM. Neuronal circuit reconstruction poses exceptional challenges to volume EM in terms of resolution, field of view, acquisition time and sample preparation. Mapping the connections between neurons in the brain is crucial for understanding information flow and information processing in the brain. However, information on the connectivity between hundreds or even thousands of neurons densely packed in neuronal microcircuits is still largely missing. Volume EM techniques such as serial section TEM, automated tape-collecting ultramicrotome, focused ion-beam scanning electron microscopy and SBEM (microtome serial block-face scanning electron microscopy) are the techniques that provide sufficient resolution to resolve ultrastructural details such as synapses and provides sufficient field of view for dense reconstruction of neuronal circuits. While volume EM techniques are advancing, they are generating large data sets on the terabyte scale that require new image processing workflows and analysis tools. In this review, we present the recent advances in SBEM for circuit reconstruction in neuroscience and an overview of existing image processing and analysis pipelines.

  2. A functional-based segmentation of human body scans in arbitrary postures.

    PubMed

    Werghi, Naoufel; Xiao, Yijun; Siebert, Jan Paul

    2006-02-01

    This paper presents a general framework that aims to address the task of segmenting three-dimensional (3-D) scan data representing the human form into subsets which correspond to functional human body parts. Such a task is challenging due to the articulated and deformable nature of the human body. A salient feature of this framework is that it is able to cope with various body postures and is in addition robust to noise, holes, irregular sampling and rigid transformations. Although whole human body scanners are now capable of routinely capturing the shape of the whole body in machine readable format, they have not yet realized their potential to provide automatic extraction of key body measurements. Automated production of anthropometric databases is a prerequisite to satisfying the needs of certain industrial sectors (e.g., the clothing industry). This implies that in order to extract specific measurements of interest, whole body 3-D scan data must be segmented by machine into subsets corresponding to functional human body parts. However, previously reported attempts at automating the segmentation process suffer from various limitations, such as being restricted to a standard specific posture and being vulnerable to scan data artifacts. Our human body segmentation algorithm advances the state of the art to overcome the above limitations and we present experimental results obtained using both real and synthetic data that confirm the validity, effectiveness, and robustness of our approach.

  3. Fine-Grain Feature Extraction from Malware's Scan Behavior Based on Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Eto, Masashi; Sonoda, Kotaro; Inoue, Daisuke; Yoshioka, Katsunari; Nakao, Koji

    Network monitoring systems that detect and analyze malicious activities as well as respond against them, are becoming increasingly important. As malwares, such as worms, viruses, and bots, can inflict significant damages on both infrastructure and end user, technologies for identifying such propagating malwares are in great demand. In the large-scale darknet monitoring operation, we can see that malwares have various kinds of scan patterns that involves choosing destination IP addresses. Since many of those oscillations seemed to have a natural periodicity, as if they were signal waveforms, we considered to apply a spectrum analysis methodology so as to extract a feature of malware. With a focus on such scan patterns, this paper proposes a novel concept of malware feature extraction and a distinct analysis method named “SPectrum Analysis for Distinction and Extraction of malware features(SPADE)”. Through several evaluations using real scan traffic, we show that SPADE has the significant advantage of recognizing the similarities and dissimilarities between the same and different types of malwares.

  4. [Limb edema and lymphoscintigraphy].

    PubMed

    Bourgeois, P; Munck, D; Belgrado, J P; Leduc, O; Leduc, A

    2003-02-01

    Lymphoscintigraphic investigations represent techniques of nuclear medicine very contributive for the management and treatment of the limb edemas, either primary or secundary. Their principle is presented and methodologies proposed in the literature are reviewed. Their diagnostic contributions are detailed. The sensitivities and specificities of several protocols of investigation are reported. Some limitations of these examinations are analyzed and discussed. Clinical indications for their use are proposed and their interest with regard to the various treatments that can be applied to these limb edemas is discussed.

  5. JKTLD: Limb darkening coefficients

    NASA Astrophysics Data System (ADS)

    Southworth, John

    2015-11-01

    JKTLD outputs theoretically-calculated limb darkening (LD) strengths for equations (LD laws) which predict the amount of LD as a function of the part of the star being observed. The coefficients of these laws are obtained by bilinear interpolation (in effective temperature and surface gravity) in published tables of coefficients calculated from stellar model atmospheres by several researchers. Many observations of stars require the strength of limb darkening (LD) to be estimated, which can be done using theoretical models of stellar atmospheres; JKTLD can help in these circumstances.

  6. High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser.

    PubMed

    Bonesi, Marco; Sattmann, Harald; Torzicky, Teresa; Zotter, Stefan; Baumann, Bernhard; Pircher, Michael; Götzinger, Erich; Eigenwillig, Christoph; Wieser, Wolfgang; Huber, Robert; Hitzenberger, Christoph K

    2012-11-01

    We report on a new swept source polarization sensitive optical coherence tomography scan engine that is based on polarization maintaining (PM) fiber technology. The light source is a Fourier domain mode locked laser with a PM cavity that operates in the 1300 nm wavelength regime. It is equipped with a PM buffer stage that doubles the fundamental sweep frequency of 54.5 kHz. The fiberization allows coupling of the scan engine to different delivery probes. In a first demonstration, we use the system for imaging human skin at an A-scan rate of 109 kHz. The system illuminates the sample with circularly polarized light and measures reflectivity, retardation, optic axis orientation, and Stokes vectors simultaneously. Furthermore, depolarization can be quantified by calculating the degree of polarization uniformity (DOPU). The high scanning speed of the system enables dense sampling in both, the x- and y-direction, which provides the opportunity to use 3D evaluation windows for DOPU calculation. This improves the spatial resolution of DOPU images considerably.

  7. Internal models of limb dynamics and the encoding of limb state

    NASA Astrophysics Data System (ADS)

    Hwang, Eun Jung; Shadmehr, Reza

    2005-09-01

    Studies of reaching suggest that humans adapt to novel arm dynamics by building internal models that transform planned sensory states of the limb, e.g., desired limb position and its derivatives, into motor commands, e.g., joint torques. Earlier work modeled this computation via a population of basis elements and used system identification techniques to estimate the tuning properties of the bases from the patterns of generalization. Here we hypothesized that the neural representation of planned sensory states in the internal model might resemble the signals from the peripheral sensors. These sensors normally encode the limb's actual sensory state in which movement errors occurred. We developed a set of equations based on properties of muscle spindles that estimated spindle discharge as a function of the limb's state during reaching and drawing of circles. We then implemented a simulation of a two-link arm that learned to move in various force fields using these spindle-like bases. The system produced a pattern of adaptation and generalization that accounted for a wide range of previously reported behavioral results. In particular, the bases showed gain-field interactions between encoding of limb position and velocity, very similar to the gain fields inferred from behavioral studies. The poor sensitivity of the bases to limb acceleration predicted behavioral results that were confirmed by experiment. We suggest that the internal model of limb dynamics is computed by the brain with neurons that encode the state of the limb in a manner similar to that expected of muscle spindle afferents.

  8. SI2N assessment of vertical ozone trends: Stability of limb/occultation data records over 1984-2013 against ground-based networks

    NASA Astrophysics Data System (ADS)

    Hubert, Daan; Lambert, Jean-Christopher; Verhoelst, Tijl; Granville, José; Keppens, Arno

    2014-05-01

    Since the first indirect solar occultation measurement of the ozone profile with Echo-1 in 1960, numerous limb/occultation viewing instruments were deployed in space over the past 50 years to measure the vertical distribution of atmospheric ozone. Among them, a few provided data records potentially suitable for documenting the evolution of the ozone layer and for improving our understanding of the interactions between changes in ozone, climate, and solar radiation. Three decades after the start of stratospheric ozone depletion by man-made chemicals, the first weak signs of slow recovery in stratospheric ozone abundance over Northern mid-latitudes were reported in the last WMO Ozone assessment, in 2010. The data collected since then, together with recent improvements of historical data records, may substantiate these initial findings and even provide hints as to how to attribute the recovery of the ozone layer. In preparation of the upcoming WMO assessment in 2014, the ozone research community set up the SPARC/IO3C/IGACO-O3/NDACC Initiative on Past Changes in the Vertical Distribution of Ozone (SI2N), to study and document those long-term changes. To increase the significance of trend studies, ozone records from measurement systems with different instrumental design and retrieval technique were merged. As a prerequisite, the stability of and consistency between these data records played a pivotal role in the SI2N effort and are the subject of this report. In this SI2N context, we present a comprehensive and systematic quality assessment of the 14 major space-based limb and occultation ozone profile records potentially suitable for ozone trend assessments, from the ground up to the middle stratosphere. All satellite records were analysed within one methodological framework. Correlative ground-based observations from the ozonesonde and lidar networks (NDACC, GAW) act as a reference standard with well-characterized quality. The application of robust statistical methods

  9. Identification-While-Scanning of a Multi-Aircraft Formation Based on Sparse Recovery for Narrowband Radar.

    PubMed

    Jiang, Yuan; Xu, Jia; Peng, Shi-Bao; Mao, Er-Ke; Long, Teng; Peng, Ying-Ning

    2016-11-23

    It is known that the identification performance of a multi-aircraft formation (MAF) of narrowband radar mainly depends on the time on target (TOT). To realize the identification task in one rotated scan with limited TOT, the paper proposes a novel identification-while-scanning (IWS) method based on sparse recovery to maintain high rotating speed and super-resolution for MAF identification, simultaneously. First, a multiple chirp signal model is established for MAF in a single scan, where different aircraft may have different Doppler centers and Doppler rates. Second, based on the sparsity of MAF in the Doppler parameter space, a novel hierarchical basis pursuit (HBP) method is proposed to obtain satisfactory sparse recovery performance as well as high computational efficiency. Furthermore, the parameter estimation performance of the proposed IWS identification method is analyzed with respect to recovery condition, signal-to-noise ratio and TOT. It is shown that an MAF can be effectively identified via HBP with a TOT of only about one hundred microseconds for IWS applications. Finally, some numerical experiment results are provided to demonstrate the effectiveness of the proposed method based on both simulated and real measured data.

  10. Identification-While-Scanning of a Multi-Aircraft Formation Based on Sparse Recovery for Narrowband Radar

    PubMed Central

    Jiang, Yuan; Xu, Jia; Peng, Shi-Bao; Mao, Er-Ke; Long, Teng; Peng, Ying-Ning

    2016-01-01

    It is known that the identification performance of a multi-aircraft formation (MAF) of narrowband radar mainly depends on the time on target (TOT). To realize the identification task in one rotated scan with limited TOT, the paper proposes a novel identification-while-scanning (IWS) method based on sparse recovery to maintain high rotating speed and super-resolution for MAF identification, simultaneously. First, a multiple chirp signal model is established for MAF in a single scan, where different aircraft may have different Doppler centers and Doppler rates. Second, based on the sparsity of MAF in the Doppler parameter space, a novel hierarchical basis pursuit (HBP) method is proposed to obtain satisfactory sparse recovery performance as well as high computational efficiency. Furthermore, the parameter estimation performance of the proposed IWS identification method is analyzed with respect to recovery condition, signal-to-noise ratio and TOT. It is shown that an MAF can be effectively identified via HBP with a TOT of only about one hundred microseconds for IWS applications. Finally, some numerical experiment results are provided to demonstrate the effectiveness of the proposed method based on both simulated and real measured data. PMID:27886055

  11. Model-based segmentation of the facial nerve and chorda tympani in pediatric CT scans

    NASA Astrophysics Data System (ADS)

    Reda, Fitsum A.; Noble, Jack H.; Rivas, Alejandro; Labadie, Robert F.; Dawant, Benoit M.

    2011-03-01

    In image-guided cochlear implant surgery an electrode array is implanted in the cochlea to treat hearing loss. Access to the cochlea is achieved by drilling from the outer skull to the cochlea through the facial recess, a region bounded by the facial nerve and the chorda tympani. To exploit existing methods for computing automatically safe drilling trajectories, the facial nerve and chorda tympani need to be segmented. The effectiveness of traditional segmentation approaches to achieve this is severely limited because the facial nerve and chorda are small structures (~1 mm and ~0.3 mm in diameter, respectively) and exhibit poor image contrast. We have recently proposed a technique to achieve this task in adult patients, which relies on statistical models of the structures. These models contain intensity and shape information along the central axes of both structures. In this work we use the same method to segment pediatric scans. We show that substantial differences exist between the anatomy of children and the anatomy of adults, which lead to poor segmentation results when an adult model is used to segment a pediatric volume. We have built a new model for pediatric cases and we have applied it to ten scans. A leave-one-out validation experiment was conducted in which manually segmented structures were compared to automatically segmented structures. The maximum segmentation error was 1 mm. This result indicates that accurate segmentation of the facial nerve and chorda in pediatric scans is achievable, thus suggesting that safe drilling trajectories can also be computed automatically.

  12. Scanning electron microscopy and energy dispersive analysis of machined denture base surfaces.

    PubMed

    Radford, D R; Walter, J D; Challacombe, S J

    1997-01-01

    To relate the characteristics of rotary instruments to the surfaces they produce, acrylic resin, Molloplast B, and Novus were investigated with energy dispersive analysis and scanning electron microscopy (secondary and backscatter images) before and after machining. The chemical composition of cutting instruments, material surfaces, and residues was identified. Machined debris embedded in Molloplast B after machining with the Molloplast stone was found to contain a mean lead content of 45%. High concentrations of barium sulphate were discovered on the arbor band-machined surface of Novus. These differences were related to clinically appropriate instrumentation, and, therefore, biocompatibility studies that intimately relate to the in vivo situation should be considered for new materials.

  13. Monolithically Integrated, Mechanically Resilient Carbon-Based Probes for Scanning Probe Microscopy

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Megerian, Krikor G.; Jennings, Andrew T.; Greer, Julia R.

    2010-01-01

    Scanning probe microscopy (SPM) is an important tool for performing measurements at the nanoscale in imaging bacteria or proteins in biology, as well as in the electronics industry. An essential element of SPM is a sharp, stable tip that possesses a small radius of curvature to enhance spatial resolution. Existing techniques for forming such tips are not ideal. High-aspect-ratio, monolithically integrated, as-grown carbon nanofibers (CNFs) have been formed that show promise for SPM applications by overcoming the limitations present in wet chemical and separate substrate etching processes.

  14. Fabrication of microstructures in aviation components with a femtosecond laser based on PZT scanning

    NASA Astrophysics Data System (ADS)

    Yang, Xiaojun; Zhao, Wei; Li, Ming; Zhao, Hualong; Zhang, Huixing; Li, Peng; Yang, Yong; Cheng, Guanghua

    2013-05-01

    Thermal defects and low precision are the main disadvantages of fabricating micro-holes, irregular holes, and micro-slots in thermostable aviation materials. We demonstrate a manufacturing method employing a femtosecond laser and piezoelectric ceramic (PZT). The production process parameters were optimized according to the metallographic and dimensional accuracy of the microstructure, which was measured by phase-contrast microscopy and scanning electron microscopy. The limitations in a conventional aeroengine, such as in the recast layer, recrystallization, and micro-cracks, which degrade the performance and service life, were resolved with a simple, controllable, and commercial method.

  15. Artificial limb connection

    NASA Technical Reports Server (NTRS)

    Owens, L. J.

    1974-01-01

    Connection simplifies and eases donning and removing artificial limb; eliminates harnesses and clamps; and reduces skin pressures by allowing bone to carry all tensile and part of compressive loads between prosthesis and stump. Because connection is modular, it is easily modified to suit individual needs.

  16. Ground-based assessment of the bias and long-term stability of 14 limb and occultation ozone profile data records

    NASA Astrophysics Data System (ADS)

    Hubert, Daan; Lambert, Jean-Christopher; Verhoelst, Tijl; Granville, José; Keppens, Arno; Baray, Jean-Luc; Bourassa, Adam E.; Cortesi, Ugo; Degenstein, Doug A.; Froidevaux, Lucien; Godin-Beekmann, Sophie; Hoppel, Karl W.; Johnson, Bryan J.; Kyrölä, Erkki; Leblanc, Thierry; Lichtenberg, Günter; Marchand, Marion; McElroy, C. Thomas; Murtagh, Donal; Nakane, Hideaki; Portafaix, Thierry; Querel, Richard; Russell, James M., III; Salvador, Jacobo; Smit, Herman G. J.; Stebel, Kerstin; Steinbrecht, Wolfgang; Strawbridge, Kevin B.; Stübi, René; Swart, Daan P. J.; Taha, Ghassan; Tarasick, David W.; Thompson, Anne M.; Urban, Joachim; van Gijsel, Joanna A. E.; Van Malderen, Roeland; von der Gathen, Peter; Walker, Kaley A.; Wolfram, Elian; Zawodny, Joseph M.

    2016-06-01

    profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we made a systematic assessment of 14 limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we considered the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a consistent and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allowed us to investigate, from the troposphere up to the stratopause, the following main aspects of satellite data quality: long-term stability, overall bias and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permitted us to quantify the overall consistency between the ozone profilers. Generally, we found that between 20 and 40 km the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are less than 5-12 % and the drifts are at most ±5 % decade-1 (or even ±3 % decade-1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause where natural variability and low ozone abundances impede a more precise analysis. In part of the stratosphere a few records deviate from the preceding general conclusions; we identified biases of 10 % and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY) and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE and possibly GOMOS and SMR as well). Furthermore, we reflected on the repercussions

  17. Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records

    NASA Astrophysics Data System (ADS)

    Hubert, D.; Lambert, J.-C.; Verhoelst, T.; Granville, J.; Keppens, A.; Baray, J.-L.; Cortesi, U.; Degenstein, D. A.; Froidevaux, L.; Godin-Beekmann, S.; Hoppel, K. W.; Kyrölä, E.; Leblanc, T.; Lichtenberg, G.; McElroy, C. T.; Murtagh, D.; Nakane, H.; Russell, J. M., III; Salvador, J.; Smit, H. G. J.; Stebel, K.; Steinbrecht, W.; Strawbridge, K. B.; Stübi, R.; Swart, D. P. J.; Taha, G.; Thompson, A. M.; Urban, J.; van Gijsel, J. A. E.; von der Gathen, P.; Walker, K. A.; Wolfram, E.; Zawodny, J. M.

    2015-07-01

    The ozone profile records of a large number of limb and occultation satellite instruments are widely used to address several key questions in ozone research. Further progress in some domains depends on a more detailed understanding of these data sets, especially of their long-term stability and their mutual consistency. To this end, we make a systematic assessment of fourteen limb and occultation sounders that, together, provide more than three decades of global ozone profile measurements. In particular, we consider the latest operational Level-2 records by SAGE II, SAGE III, HALOE, UARS MLS, Aura MLS, POAM II, POAM III, OSIRIS, SMR, GOMOS, MIPAS, SCIAMACHY, ACE-FTS and MAESTRO. Central to our work is a harmonized and robust analysis of the comparisons against the ground-based ozonesonde and stratospheric ozone lidar networks. It allows us to investigate, from the ground up to the stratopause, the following main aspects of data quality: long-term stability, overall bias, and short-term variability, together with their dependence on geophysical parameters and profile representation. In addition, it permits us to quantify the overall consistency between the ozone profilers. Generally, we find that between 20-40 km, the satellite ozone measurement biases are smaller than ±5 %, the short-term variabilities are better than 5-12 % and the drifts are at most ±5 % decade-1 (and ±3 % decade-1 for a few records). The agreement with ground-based data degrades somewhat towards the stratopause and especially towards the tropopause, where natural variability and low ozone abundancies impede a more precise analysis. A few records deviate from the preceding general remarks, in part of the stratosphere; we identify biases of 10 % and more (POAM II and SCIAMACHY), markedly higher single-profile variability (SMR and SCIAMACHY), and significant long-term drifts (SCIAMACHY, OSIRIS, HALOE, and possibly GOMOS and SMR as well). Furthermore, we reflect on the repercussions of our

  18. The Distribution of High Altitude (70KM) Ice Clouds in the Mars Atmospere from MGS TES and MOC LIMB Observations

    NASA Astrophysics Data System (ADS)

    Clancy, R. T.; Wolff, M.; Whitney, B.; Cantor, B.

    2004-11-01

    The Pathfinder descent entry detected extremely cold temperatures at 70-100 km altitudes (Schofield et al., 1997), suggesting the possibility of frequent CO2 ice cloud occurrence in the 70-80 km altitude region (Clancy and Sandor, 1998). However, prior to recent MGS limb measurements, it remained unclear whether CO2 or water ice aerosols are ever present at >60 km altitudes. Dust aerosols have been identified at such high altitudes in Mariner 9 (Anderson and Leovy, 1978), Viking (Jaquin et al., 1986), and MGS limb measurements (Clancy, 2003), associated with the 1971, 1977, and 2001 planet-encircling dust storms, respectively. The highest detached ice cloud identified from Viking limb data occurred at a projected tangent altitude of 55km, at 16S, 72W and Ls = 176° (Jaquin et al., 1986; recently modeled by Montmessin et al., 2002). The seasonal period and location of this detached limb cloud appears consistent with 55-75 km detached limb clouds that we have observed as prominent in MGS TES solarband limb scans and MGS MOC wide-angle (WA) limb images (1-3 pm local times). Their occurrence frequency approaches unity at the beginning and end of the aphelion northern summer season on Mars (centered at Ls =30° and 150° ), where they are confined to equatorial (15S-15N) latitudes and two relatively narrow longitude ranges (330-20W and 50-120W). Cloud altitudes of 65-75km are derived from the distribution of projected limb heights. Peak optical (visible) depths are quite significant (0.01) for the low pressure region of formation ( 1 microbar). It remains unclear as to their composition (water or CO2), although coadded MGS thermal IR spectra indicate potential for water ice identification and particle size information. We will present the spatial and temporal distribution of these mesospheric clouds indicated in the MSG TES and MOC visible limb data, and derived vertical profiles of optical depth and particle size based upon a monte carlo spherical RT analysis of the

  19. A novel method of drift-scanning stars suppression based on the standardized linear filter

    NASA Astrophysics Data System (ADS)

    Lin, Jianlin; Ping, Xijian; Hou, Guanghua; Ma, Debao

    2011-11-01

    A large number of stars in the drift-scanning star image have interfered with the detection of small target, this paper proposes an adaptive linear filtering method to achieve the small target detection by suppressing the stars. Firstly, the characteristics of stars, interest target and noise three different representative objects in the star image are analyzed, then the standardized linear filter is constructed to suppress the stars. For the purpose of decreasing the influence region of stars filtering uniformly, a gradient linear filter is constructed to modify the stars suppression method with the standardized linear filter. Then the filter parameter selection method is given. Finally, a multi-frame target track experiment on the real drift-scanning data is made to testify the validity of the proposed method. With the processing results of different methods, it has been showed that the proposed method for suppressing stars with different length and lean angle has a better effect, higher robustness and easier application than the others.

  20. A near-field scanning microwave microscope based on a superconducting resonator for low power measurements.

    PubMed

    de Graaf, S E; Danilov, A V; Adamyan, A; Kubatkin, S E

    2013-02-01

    We report on the design and performance of a cryogenic (300 mK) near-field scanning microwave microscope. It uses a microwave resonator as the near-field sensor, operating at a frequency of 6 GHz and microwave probing amplitudes down to 100 μV, approaching low enough photon population (N ∼ 1000) of the resonator such that coherent quantum manipulation becomes feasible. The resonator is made out of a miniaturized distributed fractal superconducting circuit that is integrated with the probing tip, micromachined to be compact enough such that it can be mounted directly on a quartz tuning-fork, and used for parallel operation as an atomic force microscope (AFM). The resonator is magnetically coupled to a transmission line for readout, and to achieve enhanced sensitivity we employ a Pound-Drever-Hall measurement scheme to lock to the resonance frequency. We achieve a well localized near-field around the tip such that the microwave resolution is comparable to the AFM resolution, and a capacitive sensitivity down to 6.4 × 10(-20) F/Hz, limited by mechanical noise. We believe that the results presented here are a significant step towards probing quantum systems at the nanoscale using near-field scanning microwave microscopy.

  1. Height control of laser metal-wire deposition based on iterative learning control and 3D scanning

    NASA Astrophysics Data System (ADS)

    Heralić, Almir; Christiansson, Anna-Karin; Lennartson, Bengt

    2012-09-01

    Laser Metal-wire Deposition is an additive manufacturing technique for solid freeform fabrication of fully dense metal structures. The technique is based on robotized laser welding and wire filler material, and the structures are built up layer by layer. The deposition process is, however, sensitive to disturbances and thus requires continuous monitoring and adjustments. In this work a 3D scanning system is developed and integrated with the robot control system for automatic in-process control of the deposition. The goal is to ensure stable deposition, by means of choosing a correct offset of the robot in the vertical direction, and obtaining a flat surface, for each deposited layer. The deviations in the layer height are compensated by controlling the wire feed rate on next deposition layer, based on the 3D scanned data, by means of iterative learning control. The system is tested through deposition of bosses, which is expected to be a typical application for this technique in the manufacture of jet engine components. The results show that iterative learning control including 3D scanning is a suitable method for automatic deposition of such structures. This paper presents the equipment, the control strategy and demonstrates the proposed approach with practical experiments.

  2. Sensor for In-Motion Continuous 3D Shape Measurement Based on Dual Line-Scan Cameras

    PubMed Central

    Sun, Bo; Zhu, Jigui; Yang, Linghui; Yang, Shourui; Guo, Yin

    2016-01-01

    The acquisition of three-dimensional surface data plays an increasingly important role in the industrial sector. Numerous 3D shape measurement techniques have been developed. However, there are still limitations and challenges in fast measurement of large-scale objects or high-speed moving objects. The innovative line scan technology opens up new potentialities owing to the ultra-high resolution and line rate. To this end, a sensor for in-motion continuous 3D shape measurement based on dual line-scan cameras is presented. In this paper, the principle and structure of the sensor are investigated. The image matching strategy is addressed and the matching error is analyzed. The sensor has been verified by experiments and high-quality results are obtained. PMID:27869731

  3. Modeling and simulation of blazed grating based on MEMS scanning micro-mirror for NIR micro-spectrometer

    NASA Astrophysics Data System (ADS)

    Zhou, Ying; Wen, Zhiyu; Yang, Tingyan; Lei, Hongjie

    2015-11-01

    Near infrared micro-spectrometer (NIRMS) as a vital detection equipment for various elements has been investigated over the last few years. Traditional MEMS NIRMS employs CCD array detectors for NIR spectrum collection and this leads to higher fabrication cost. In this paper, to ensure the higher diffraction efficiency as well as lower fabrication cost, a novel blazed grating based on MEMS scanning micro-mirror (SMM) is proposed. By our design method, the NIRMS needs only one single InGaAs detector photo diode to collect NIR spectrum and ensure the high diffraction efficiency. Our results show that the diffraction efficiency of the blazed grating is almost 50% and the peak value reaches to 90% in the range of 900-2,100 nm while the optical scanning angle is 14.2°.

  4. Sensor for In-Motion Continuous 3D Shape Measurement Based on Dual Line-Scan Cameras.

    PubMed

    Sun, Bo; Zhu, Jigui; Yang, Linghui; Yang, Shourui; Guo, Yin

    2016-11-18

    The acquisition of three-dimensional surface data plays an increasingly important role in the industrial sector. Numerous 3D shape measurement techniques have been developed. However, there are still limitations and challenges in fast measurement of large-scale objects or high-speed moving objects. The innovative line scan technology opens up new potentialities owing to the ultra-high resolution and line rate. To this end, a sensor for in-motion continuous 3D shape measurement based on dual line-scan cameras is presented. In this paper, the principle and structure of the sensor are investigated. The image matching strategy is addressed and the matching error is analyzed. The sensor has been verified by experiments and high-quality results are obtained.

  5. HIGH RESOLUTION AND FAST SCANNING SQUID BASED NON-DESTRUCTIVE INSPECTION SYSTEM OF NIOBIUM SHEETS FOR SRF CAVITIES

    SciTech Connect

    SHU, QUAN-SHENG

    2008-06-08

    Applications in high energy physics accelerators and other fields require the use of thousands of superconducting RF (SRF) cavities that are made of high purity Nb material and the purity of niobium is critical for these cavities to reach the highest accelerating fields. Tantalum is the most prolific of metal inclusions, which can cause thermal breakdown and prevent the cavities from reaching their theoretical performance limits of 45-50 MV/m, and DOE Labs are searching for a technology that could detect small impurities in superconducting Nb sheets reaching the highest possible accelerating fields. The proposed innovative SQUID-based Nondestructive system can scan Niobium sheets used in the manufacturing of SRF cavities with both high speed and high resolution. A highly sensitive SQUID system with a gradiometer probe, non-magnetic dewar, data acquisition system, and a scanning system will be developed for fast detection of impurities in planar Nb sheets. In phase I, we will modify our existing SQUID-based eddy current system to detect 100 micron size Ta defects and a great effort will focus on achieving fast scanning of a large number of niobium sheets in a shorter time and with reasonable resolution. An older system operated by moving the sample 1 mm, stopping and waiting for 1-2 seconds, then activating a measurement by the SQUID after the short settle time is modified. A preliminary designed and implemented a SQUID scanning system that is fast and is capable of scanning a 30 cm x 30 cm Nb sheet in 15 minutes by continuously moving the table at speeds up to 10 mm/s while activating the SQUID at 1mm interval is modified and reached the Phase I goal of 100mm resolution. We have successfully demonstrated the feasibility that a fast speed SQUID scanner without sacrificing the resolution of detection can be done, and a data acquisition and analysis system is also preliminary developed. The SQUID based scanner will help reach the highest accelerating field in SRF

  6. Resolving the lateral component of blood flow velocity based on ultrasound speckle size change with scan direction and speed.

    PubMed

    Xu, Tiantian; Bashford, Gregory R

    2009-01-01

    Conventional blood flow velocity measurement using ultrasound is capable of resolving the axial component (i.e., that aligned with the ultrasound propagation direction) of the blood flow velocity vector. However, these Doppler-based methods are incapable of detecting blood flow in the direction normal to the ultrasound beam. In addition, these methods require repeated pulse-echo interrogation at the same spatial location. In this paper, we introduce a method which estimates the lateral component of blood flow within a single image frame using the observation that the speckle pattern corresponding to the blood reflectors (typically red blood cells) stretches (i.e., is "smeared") if the blood is moving in the same direction as the electronically-controlled transducer line selection in a 2D image. The situation is analogous to the observed elongation of a subject photographed with a moving camera. Here, we develop a relationship between speckle size, scan speed, and blood flow velocity. Experiments were performed with a blood flow phantom and high-frequency transducer of a commercially available ultrasound machine. Data was captured through an interface allowing access to the raw beam formed data. Blood flow with velocities ranging from 15 to 40 cm/s were investigated in this paper. Results show that there is a linear relationship between the reciprocal of the stretch factor and blood flow velocity. Two scan speeds were used in our experiments. When the scan velocity is 64.8 cm/s, compared with the theoretical model, fitting results based on experimental data gave us a linear relationship with average flow estimation error of 1.74+/-1.48 cm/s. When the scan velocity is 37.4 cm/s, the average estimation error is 0.65+/-0.45 cm/s.

  7. Six degree-of-freedom scanning supports and manipulators based on parallel robots

    NASA Astrophysics Data System (ADS)

    Comin, Fabio

    1995-02-01

    The exploitation of third generation SR sources heavily relies on accurate and stable positioning and scanning of samples and optical elements. In some cases, active feedback is also necessary. Normally, these tasks are carried out by serial addition of individual components, each of them providing a well-defined excursion path. On the contrary, the exploitation of the concept of parallel robots, structures in close cinematic chain, permits us to follow any given trajectory in the six-dimensional space with a large increase in accuracy and stiffness. At ESRF, the parallel robot architecture conceived some tens of years ago for flight simulators has been adapted to both actively align and operate optical elements of considerable weight and position small samples in ultrahigh vacuum. The performance of these devices gives results far superior to the initial specification and a variety of drive mechanisms are being developed to fit the different needs of the ESRF beamlines.

  8. Scanning thermal microscopy based on a modified atomic force microscope combined with pyroelectric detection

    NASA Astrophysics Data System (ADS)

    Antoniow, J.-S.; Chirtoc, M.; Trannoy, N.; Raphael, O.; Pelzl, J.

    2005-06-01

    We propose a novel approach in scanning thermal microscopy of layered samples. The thermal probe (ThP) (Wollaston wire) acts as a local a.c. heat source at the front of a sample layer deposited on a pyroelectric (PE) sensor. The PE signal is proportional to the heat wave transmitted through the sample. The ThP and PE signals can be used to generate complementary thermal conductivity maps and with some restrictions, thermal diffusivity maps of the sample. Additionally, the topography map is obtained in the usual way from the atomic force microscope. We give the theoretical background for the interpretation of PE signal obtained at low and at high frequency, and we demonstrate that it carries information on the thermal diffusivity of a test sample (12 μm thick PET polymer sheet). Finally, we discuss the contributions of heat transfer channels between ThP and sample, and the role of contact thermal resistance.

  9. Sub-Rayleigh imaging via undersampling scanning based on sparsity constraints

    NASA Astrophysics Data System (ADS)

    Xue, Chang-Bin; Yao, Xu-Ri; Li, Long-Zhen; Liu, Xue-Feng; Yu, Wen-Kai; Guo, Xiao-Yong; Zhai, Guang-Jie; Zhao, Qing

    2017-02-01

    We demonstrate that, by undersampling scanning object with a reconstruction algorithm related to compressed sensing, an image with the resolution exceeding the finest resolution defined by the numerical aperture of the system can be obtained. Experimental results show that the measurements needed to achieve sub-Rayleigh resolution enhancement can be less than 10% of the pixels of the object. This method offers a general approach applicable to point-by-point illumination super-resolution techniques. Project supported by the National Natural Science Foundation of China (Grant Nos. 61605218 and 61601442), the National Defense Science and Technology Innovation Foundation of the Chinese Academy of Sciences (Grant No. CXJJ-16S047), and the National Major Scientific Instruments Development Project of China (Grant No. 2013YQ030595).

  10. A flexible Labview{trademark}-based data acquisition and analysis system for scanning microscopy

    SciTech Connect

    Daniel H. Morse; Arlyn J. Antolak; Graham S. Bench; Mark L. Roberts

    1998-10-08

    A new data analysis system has been developed with computer-controlled beam and sample positioning, video sample imaging, multiple large solid angle detectors for x-rays and gamma-rays, and surface barrier detectors for charged particles. The system uses the LabVIEW{trademark} programming language allowing it to be easily ported between different computer operating systems. In the present configuration, digital signal processors are directly interfaced to a SCSI CAMAC controller. However, the modular software design permits the substitution of other hardware with LabVIEW-supported drivers. On-line displays of histogram and two-dimensional elemental map images provide a user-friendly data acquisition interface. Subregions of the two-dimensional maps may be selected interactively for detailed analysis or for subsequent scanning. Off-line data processing of archived data currently yields elemental maps, analyzed spectra and reconstructions of tomographic data.

  11. Fiber laser-based scanning lidar for space rendezvous and docking.

    PubMed

    Luo, Yuan; He, Yan; Gao, Min; Zhou, Cuiyun; Zang, Huaguo; Lei, Linjun; Xie, Kedi; Yang, Yan; Shi, Wei; Hou, Xia; Chen, Weibiao

    2015-03-20

    Lidar systems have played an important role in space rendezvous and docking (RVD). A new type of scanning lidar is developed using a high-repetition-rate pulsed fiber laser and a position detector. It will be a candidate for autonomous space RVD between two spacecrafts. The lidar can search and track cooperative targets in a large region without artificial guidance. The lidar's operational range spans from 18 m to 20 km, and the relative angle between two aircrafts can be measured with high accuracy. A novel fiber laser with tunable pulse energy and repetition rate is developed to meet the wide dynamic detection range of the lidar. This paper presents the lidar system's composition, performance, and experimental results in detail.

  12. Friedel oscillations in graphene-based systems probed by Scanning Tunneling Microscopy

    NASA Astrophysics Data System (ADS)

    Mallet, Pierre; Brihuega, Iván; Cherkez, Vladimir; Gómez-Rodríguez, Jose Marìa; Veuillen, Jean-Yves

    2016-03-01

    For the last 25 years, scientists have demonstrated the capabilities of Scanning Tunneling Microscopy (STM) to visualize in real space the response of a two-dimensional electron gas to atomic-scale impurities. The analysis of the Friedel oscillations surrounding the impurities yields valuable information regarding the elastic scattering properties, the band structure, the doping level and the symmetry of the electronic states in the two-dimensional host system. We will address in this article the use of this technique for probing the electronic properties of graphene, the star two-dimensional compound of the last decade. In particular, we will emphasize how this technique can be pushed up to unravel the electronic pseudospin, a distinctive degree of freedom of graphene's Dirac fermions.

  13. Renal scan

    MedlinePlus

    ... and urinate often to help remove the radioactive material from the body. How to Prepare for the Test Tell your health care provider if you take ... drink additional fluids before the scan. How the Test will ... into the vein. However, you will not feel the radioactive material. The scanning table may be hard and cold. ...

  14. Comparison of field and airborne laser scanning based crown cover estimates across land cover types in Kenya

    NASA Astrophysics Data System (ADS)

    Heiskanen, J.; Korhonen, L.; Hietanen, J.; Heikinheimo, V.; Schafer, E.; Pellikka, P. K. E.

    2015-04-01

    Tree crown cover (CC) provides means for the continuous land cover characterization of complex tropical landscapes with multiple land uses and variable degrees of degradation. It is also a key parameter in the international forest definitions that are basis for monitoring global forest cover changes. Recently, airborne laser scanning (ALS) has emerged as a practical method for accurate CC mapping, but ALS derived CC estimates have rarely been assessed with field data in the tropics. Here, our objective was to compare the various field and ALS based CC estimates across multiple land cover types in the Taita Hills, Kenya. The field data was measured from a total of 178 sample plots (0.1 ha) in 2013 and 2014. The most accurate field measurement method, line intersect sampling using Cajanus tube, was used in 37 plots. Other methods included CC estimate based on the tree inventory data (144 plots), crown relascope (43 plots) and hemispherical photography (30 plots). Three ALS data sets, including two scanners and flying heights, were acquired concurrently with the field data collection. According to the results, the first echo cover index (FCI) from ALS data had good agreement with the most accurate field based CC estimates (RMSD 7.1% and 2.7% depending on the area and scan). The agreement with other field based methods was considerably worse. Furthermore, we observed that ALS cover indices were robust between the different scans in the overlapping area. In conclusion, our results suggest that ALS provides a reliable method for continuous CC mapping across tropical land cover types although dense shrub layer and tree-like herbaceous plants can cause overestimation of CC.

  15. Piezoelectric bimorph-based scanner in the tip-scan mode for high speed atomic force microscope.

    PubMed

    Zhao, Jianyong; Gong, Weitao; Cai, Wei; Shang, Guangyi

    2013-08-01

    A piezoelectric bimorph-based scanner operating in tip-scan mode for high speed atomic force microscope (AFM) is first presented. The free end of the bimorph is used for fixing an AFM cantilever probe and the other one is mounted on the AFM head. The sample is placed on the top of a piezoelectric tube scanner. High speed scan is performed with the bimorph that vibrates at the resonant frequency, while slow scanning is carried out by the tube scanner. The design and performance of the scanner is discussed and given in detailed. Combined with a commercially available data acquisition system, a high speed AFM has been built successfully. By real-time observing the deformation of the pores on the surface of a commercial piezoelectric lead zirconate titanate (PZT-5) ceramics under electric field, the dynamic imaging capability of the AFM is demonstrated. The results show that the notable advantage of the AFM is that dynamic process of the sample with large dimensions can be easily investigated. In addition, this design could provide a way to study a sample in real time under the given experimental condition, such as under an external electric field, on a heating stage, or in a liquid cell.

  16. ATHLETE: A Limbed Vehicle for Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian H.

    2012-01-01

    As part of the Human-Robot Systems project funded by NASA, the Jet Propulsion Laboratory has developed a vehicle called ATHLETE: the All-Terrain Hex-Limbed Extra-Terrestrial Explorer. Each vehicle is based on six wheels at the ends of six multi-degree-of-freedom limbs. Because each limb has enough degrees of freedom for use as a general-purpose leg, the wheels can be locked and used as feet to walk out of excessively soft or other extreme terrain. Since the vehicle has this alternative mode of traversing through or at least out of extreme terrain, the wheels and wheel actuators can be sized for nominal terrain. There are substantial mass savings in the wheel and wheel actuators associated with designing for nominal instead of extreme terrain. These mass savings are comparable-to or larger-than the extra mass associated with the articulated limbs. As a result, the entire mobility system, including wheels and limbs, can be about 25% lighter than a conventional mobility chassis. A side benefit of this approach is that each limb has sufficient degrees-of-freedom to use as a general-purpose manipulator (hence the name "limb" instead of "leg"). Our prototype ATHLETE vehicles have quick-disconnect tool adapters on the limbs that allow tools to be drawn out of a "tool belt" and maneuvered by the limb.

  17. Regeneration inducers in limb regeneration.

    PubMed

    Satoh, Akira; Mitogawa, Kazumasa; Makanae, Aki

    2015-08-01

    Limb regeneration ability, which can be observed in amphibians, has been investigated as a representative phenomenon of organ regeneration. Recently, an alternative experimental system called the accessory limb model was developed to investigate early regulation of amphibian limb regeneration. The accessory limb model contributed to identification of limb regeneration inducers in urodele amphibians. Furthermore, the accessory limb model may be applied to other species to explore universality of regeneration mechanisms. This review aims to connect the insights recently gained to emboss universality of regeneration mechanisms among species. The defined molecules (BMP7 (or2) + FGF2 + FGF8) can transform skin wound healing to organ (limb) regeneration responses. The same molecules can initiate regeneration responses in some species.

  18. Congenital abnormalities associated with limb deficiency defects: a population study based on cases from the Hungarian Congenital Malformation Registry (1975-1984).

    PubMed

    Evans, J A; Vitez, M; Czeizel, A

    1994-01-01

    Limb deficiency defects (LD) occurring among 1,575,904 births in Hungary during 1975-1984 were reviewed. The overall birth prevalence of LD was 1 in 1,816. This paper discusses the nature and distribution of the limb and other defects in the 275 (32%) children who had structural malformations in other systems. Two main forms of classification were used: morphologic and causal. Additional malformations were most commonly seen in infants with amelia, rudimentary limb (RL), radial/tibial (RT), intercalary or central axis (CA) LD and rarely in those with terminal transverse (TT) or ulnar/fibular (UF) defects. Upper limbs (81%) were involved significantly more often than lower limbs (42%) and there were more right-sided defects (83% vs. 71%) due to an excess of right arm involvement especially with radial ray and split hand anomalies. Single limb involvement was relatively common with amelia (88%), UF (82%), RT (50%), and TT (50%) defects. With other LD, multimelic involvement was more characteristic. This was usually symmetric with intercalary and RL defects but asymmetric with CA anomalies and digital deficiencies (DD). From a causal perspective, 17% of cases had genetic disorders, 52% had recognized associations, anomalies, sequences, environmental causes or patterns of unknown origin, and 31% had unknown patterns of malformations. The commonest entities were amnion disruption sequence (16% of cases) and VACTERL association (8%). Both of these disorders showed unusual temporal distribution. As anticipated, patterns of malformations differed with the type of LD. Amelia and digital amputations were often seen with body wall defects, atypical anencephaly or encephalocele, and cleft lip reflecting amnion disruption. Rudimentary limb was seen with anencephaly, omphalocele, renal agenesis, aberrant genitalia, and imperforate anus, reflecting defects of blastogenesis including the cloacal exstrophy and caudal regression sequences and Schisis association. Radial

  19. An Eye-Blinking-Based Beamforming Control Protocol for Hearing Aid Users With Neurological Motor Disease or Limb Amputation.

    PubMed

    Yoon, Jungmin; Nam, Kyoung Won; Lee, Jun Chang; Jang, Dong Pyo; Kim, In Young

    2017-02-01

    For hearing-impaired individuals with neurological motor deficits or finger/arm amputation due to accident or disease, hearing aid adjustment using a conventional finger manipulation-based remote controller is unavailable, and a more dedicated, hands-free alternative is required. In this study, we propose an eye-blinking-based beamforming control scheme for hearing aid users. Three electroencephalogram signals measured around the ears were utilized to detect eye-blinking patterns based on a three-layer artificial neural network. The performance of the proposed control scheme was evaluated by both subjective experiments and objective index comparison tests in simulated situations. Experimental results from the subjective test demonstrated that without the pretraining phase, the accuracy and latency time were 68.57 ± 18.50% and 10.06 ± 0.94 s, respectively; in contrast, after the pretraining phase, both the accuracy and latency time were improved to 91.00 ± 4.69% and 8.60 ± 1.05 s, respectively. In index comparison tests, the proposed control scheme exhibited improvements in the signal-to-noise ratio (SNR) as well as the segmental SNR in all tested situations, as compared to a conventional forward-focusing beamforming algorithm. We believe that the proposed control scheme provides a novel, hands-free way in which to control the operation of hearing aids for hearing-impaired patients with additional motor deficits or amputation.

  20. Markerless motion capture and measurement of hand kinematics: validation and application to home-based upper limb rehabilitation.

    PubMed

    Metcalf, Cheryl D; Robinson, Rebecca; Malpass, Adam J; Bogle, Tristan P; Dell, Thomas A; Harris, Chris; Demain, Sara H

    2013-08-01

    Dynamic movements of the hand, fingers, and thumb are difficult to measure due to the versatility and complexity of movement inherent in function. An innovative approach to measuring hand kinematics is proposed and validated. The proposed system utilizes the Microsoft Kinect and goes beyond gesture recognition to develop a validated measurement technique of finger kinematics. The proposed system adopted landmark definition (validated through ground truth estimation against assessors) and grip classification algorithms, including kinematic definitions (validated against a laboratory-based motion capture system). The results of the validation show 78% accuracy when identifying specific markerless landmarks. In addition, comparative data with a previously validated kinematic measurement technique show accuracy of MCP ± 10° (average absolute error (AAE) = 2.4°), PIP ± 12° (AAE = 4.8°), and DIP ± 11° (AAE = 4.8°). These results are notably better than clinically based alternative manual measurement techniques. The ability to measure hand movements, and therefore functional dexterity, without interfering with underlying composite movements, is the paramount objective to any bespoke measurement system. The proposed system is the first validated markerless measurement system using the Microsoft Kinect that is capable of measuring finger joint kinematics. It is suitable for home-based motion capture for the hand and, therefore, achieves this objective.

  1. Gradients of signalling in the developing limb.

    PubMed

    Towers, Matthew; Wolpert, Lewis; Tickle, Cheryll

    2012-04-01

    The developing limb is one of the first systems where it was proposed that a signalling gradient is involved in pattern formation. This gradient for specifying positional information across the antero-posterior axis is based on Sonic hedgehog signalling from the polarizing region. Recent evidence suggests that Sonic hedgehog signalling also specifies positional information across the antero-posterior axis by a timing mechanism acting in parallel with graded signalling. The progress zone model for specifying proximo-distal pattern, involving timing to provide cells with positional information, continues to be challenged, and there is further evidence that graded signalling by retinoic acid specifies the proximal part of the limb. Other recent papers present the first evidence that gradients of signalling by Wnt5a and FGFs govern cell behaviour involved in outgrowth and morphogenesis of the developing limb.

  2. Deciphering skeletal patterning: clues from the limb.

    PubMed

    Mariani, Francesca V; Martin, Gail R

    2003-05-15

    Even young children can distinguish a Tyrannosaurus rex from a Brontosaurus by observing differences in bone size, shape, number and arrangement, that is, skeletal pattern. But despite our extensive knowledge about cartilage and bone formation per se, it is still largely a mystery how skeletal pattern is established. Much of what we do know has been learned from studying limb development in chicken and mouse embryos. Based on the data from such studies, models for how limb skeletal pattern is established have been proposed and continue to be hotly debated.

  3. Limb Correction of RGB Composite Imagery for Improved Interpretation

    NASA Technical Reports Server (NTRS)

    Elmer, Nicholas; Berndt, Emily; Jedlovec, Gary; Lafontaine, Frank; Naeger, Aaron

    2014-01-01

    RGB (Red-Green-Blue) imagery, created by integrating several spectral channels into one composite image, is currently used by the operational weather community to aid in quick, real-time analysis of atmospheric processes. However, the limb effect - a result of an increasing optical path length of the absorbing atmosphere between the satellite and the earth as scan angle increases - interferes with the qualitative interpretation of RGB composites at large scan angles. It also makes the comparison of similar products from multiple satellite sensors difficult. Recent work has indicated that correcting for the limb effect in the basic channel imagery using simple statistical relationships greatly improves the utility of the derived RGB imagery. However, it is hypothesized that the limb correction coefficients vary with respect to latitude, season, cloud cover, and surface albedo. This poster will highlight an improved approach to the limb correction of RGB imagery using varying coefficients. The Joint Center for Satellite and Data Assimilation (JCSDA) Community Radiative Transfer Model (CRTM) was used to simulate top of atmosphere brightness temperatures at varying scan angles for infrared channels corresponding to the Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS), and Meteosat-10 Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensors. A subset of European Center for Medium-Range Weather Forecasts (ECMWF) temperature, specific humidity, and ozone mixing ratio profiles from March 2013 through February 2014 were used as input to the CRTM. The simulated brightness temperatures were used to determine the best fit slope of the linear relationship between the natural log of the cosine of the scan angle and the difference of the simulated brightness temperature at nadir and on the limb. The correction coefficients were then analyzed for variability with respect to latitude, season

  4. Design and implementation of fiber-based multiphoton endoscopy with microelectromechanical systems scanning

    NASA Astrophysics Data System (ADS)

    Tang, Shuo; Jung, Woonggyu; McCormick, Daniel; Xie, Tuqiang; Su, Jiangping; Ahn, Yeh-Chan; Tromberg, Bruce J.; Chen, Zhongping

    2009-05-01

    A multiphoton endoscopy system has been developed using a two-axis microelectromechanical systems (MEMS) mirror and double-cladding photonic crystal fiber (DCPCF). The MEMS mirror has a 2-mm-diam, 20-deg optical scanning angle, and 1.26-kHz and 780-Hz resonance frequencies on the x and y axes. The maximum number of resolvable focal spots of the MEMS scanner is 720×720 on the x and y axes, which indicates that the MEMS scanner can potentially support high-resolution multiphoton imaging. The DCPCF is compared with standard single-mode fiber and hollow-core photonic bandgap fiber on the basis of dispersion, attenuation, and coupling efficiency properties. The DCPCF has high collection efficiency, and its dispersion can be compensated by grating pairs. Three configurations of probe design are investigated, and their imaging quality and field of view are compared. A two-lens configuration with a collimation and a focusing lens provides the optimum imaging performance and packaging flexibility. The endoscope is applied to image fluorescent microspheres and bovine knee joint cartilage.

  5. A total station spatial positioning method based on rotary laser scanning and ultrasonic ranging.

    PubMed

    Wu, Jun; Zhu, Jigui; Yu, Zhijing; Zhuge, Jingchang; Xue, Bin

    2016-11-01

    Total station spatial coordinator measuring technology is extensively applied in the large-scale measurement of industrial assembly and manufacturing for its flexibility and adaptability. The existing total station technology has some principal limits such as poor efficiency and single tasking; in order to achieve the total station spatial coordinator measuring technology with the advantages of multi-task, real-time measurement, and high accuracy, this paper presents a novel total station measurement method by using multi-laser plane constraints established through rotating planar planes and distance information obtained with an ultrasonic ranging method. With the spatial divergence angles of the optoelectronic scanning and ultrasonic arrays, this method can measure the spatial coordinates in multi-task and real-time with a single station and a portable target bar. Experimental results show that the proposed method is feasible and valid with satisfactory accuracy. The maximum distance measurement error is less than 0.2 mm in a volume that is 5 m far away from the station.

  6. Robust Dead Reckoning System for Mobile Robots Based on Particle Filter and Raw Range Scan

    PubMed Central

    Duan, Zhuohua; Cai, Zixing; Min, Huaqing

    2014-01-01

    Robust dead reckoning is a complicated problem for wheeled mobile robots (WMRs), where the robots are faulty, such as the sticking of sensors or the slippage of wheels, for the discrete fault models and the continuous states have to be estimated simultaneously to reach a reliable fault diagnosis and accurate dead reckoning. Particle filters are one of the most promising approaches to handle hybrid system estimation problems, and they have also been widely used in many WMRs applications, such as pose tracking, SLAM, video tracking, fault identification, etc. In this paper, the readings of a laser range finder, which may be also interfered with by noises, are used to reach accurate dead reckoning. The main contribution is that a systematic method to implement fault diagnosis and dead reckoning in a particle filter framework concurrently is proposed. Firstly, the perception model of a laser range finder is given, where the raw scan may be faulty. Secondly, the kinematics of the normal model and different fault models for WMRs are given. Thirdly, the particle filter for fault diagnosis and dead reckoning is discussed. At last, experiments and analyses are reported to show the accuracy and efficiency of the presented method. PMID:25192318

  7. A total station spatial positioning method based on rotary laser scanning and ultrasonic ranging

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Zhu, Jigui; Yu, Zhijing; Zhuge, Jingchang; Xue, Bin

    2016-11-01

    Total station spatial coordinator measuring technology is extensively applied in the large-scale measurement of industrial assembly and manufacturing for its flexibility and adaptability. The existing total station technology has some principal limits such as poor efficiency and single tasking; in order to achieve the total station spatial coordinator measuring technology with the advantages of multi-task, real-time measurement, and high accuracy, this paper presents a novel total station measurement method by using multi-laser plane constraints established through rotating planar planes and distance information obtained with an ultrasonic ranging method. With the spatial divergence angles of the optoelectronic scanning and ultrasonic arrays, this method can measure the spatial coordinates in multi-task and real-time with a single station and a portable target bar. Experimental results show that the proposed method is feasible and valid with satisfactory accuracy. The maximum distance measurement error is less than 0.2 mm in a volume that is 5 m far away from the station.

  8. Micromorphology of cactus-pear (Opuntia ficus-indica (L.) Mill) cladodes based on scanning microscopies.

    PubMed

    Ben Salem-Fnayou, Asma; Zemni, Hassène; Nefzaoui, Ali; Ghorbel, Abdelwahed

    2014-01-01

    Cladode ultrastructural features of two prickly and two spineless Opuntia ficus-indica cultivars were examined using environmental scanning electron and atomic force microscopies. Observations focused on cladode as well as spine and glochid surface micromorphologies. Prickly cultivars were characterized by abundant cracked epicuticular wax deposits covering the cladode surface, with an amorphous structure as observed by AFM, while less abundant waxy plates were observed by ESEM on spineless cultivar cladodes. Further AFM observations allowed a rough granular and crystalloid epicuticular wax structure to be distinguished in spineless cultivars. Regarding spine micromorphology, prickly cultivars had strong persistent spines, observed by ESEM as a compact arrangement of oblong epidermal cells with a rough granular structure. However, deciduous spines in spineless cultivars had a broken transversely fissured epidermis covering a parallel arrangement of fibres. Through AFM, the deciduous spine surface presented an irregular hilly and smooth microrelief while persistent spines exhibited rough helical filamentous prints. ESEM and AFM studies of cladode surfaces from prickly and spineless cactus pear cultivars revealed valuable micro-morphological details that ought to be extended to a large number of O. ficus-indica cultivars.

  9. Laser scanning confocal microscopy and laser tweezers based experiments to understand dentine-bacteria interactions

    NASA Astrophysics Data System (ADS)

    Peng, Sum Chee; Mohanty, Samarendra; Gupta, P. K.; Kishen, Anil

    2007-02-01

    Failure of endodontic treatment is commonly due to Enterococcal infection. In this study influence of chemical treatments of type-I collagen membrane by chemical agents commonly used in endodontic treatment on Enterococcus faecalis cell adherence was evaluated. In order to determine the change in number of adhering bacteria after chemical treatment, confocal laser scanning microscopy was used. For this, overnight culture of E faecalis in All Culture broth was applied to chemically treated type-I collagen membrane. It was found that Ca(OH) II treated groups had statistically significant (p value=0.05) increase in population of bacteria adherence. The change in adhesion force between bacteria and collagen was determined by using optical tweezers (1064 nm). For this experiment, Type-I collagen membrane was soaked for 5 mins in a media that contained 50% all culture media and 50% saturated Ca(OH) II . The membrane was spread on the coverslip, on which diluted bacterial suspension was added. The force of laser tweezers on the bacteria was estimated at different trap power levels using viscous drag method and trapping stiffness was calculated using Equipartition theorem method. Presence of Ca(OH) II was found to increase the cell-substrate adherence force from 0.38pN to >2.1pN. Together, these experiments show that it was highly probable that the increase in adherence to collagen was due to a stronger adhesion in the presence of Ca (OH) II.

  10. Development of a scanning near-field infrared microscope based on a free electron laser

    SciTech Connect

    Hong, M.K.; Erramilli, S.; Jeung, A.

    1995-12-31

    Infrared spectroscopy is one of the most sensitive technique available for identifying and characterizing organic materials. Most molecules exhibit a large number of well-resolved strongly absorbing spectral lines in the mid-IR region of the spectrum. In addition to our own efforts described last year, Creuzet et al have also been working on combining infrared spectroscopy with sub-micron spatial resolution imaging. Scanning Near Field Infrared Microscopy (SNIM) when combined with high brightness tunable FEL radiation, provides a powerful new research tool. We have developed two new probes for use in SNIM. The first are chalcogenide fibers capable of transmitting images in the 2-12 {mu} range. At the Stanford picosecond Free Electron Laser, we have successfully obtained images of metal surfaces and of collagen fibers on diamond at a wavelength of 5.01 {mu}, with a nominal spatial resolution of 0.5 {mu} demonstrating that near field imaging can be obtained on biological samples. At a wavelength of 6.3{mu}, we found that the chalcogenide fibers are limited in their ability to withstand high powers, most likely because of the presence of absorption bands in the polyimide coating used to sheath the brittle fibers. In collaboration with Prof J. Harrington (Rutgers University), we have also developed hollow glass capillaries with metal coated on the inside. These probes are able to withstand significantly higher powers, and can function to longer wavelengths, out into the Far IR region.

  11. Scientific investigations with the data base HEAO-1 scanning modulator collimator

    NASA Technical Reports Server (NTRS)

    Schwartz, Daniel A.

    1992-01-01

    The hardware specification for the Scanning Modulation Collimator (MC) experiment on HEAO-1 was to measure positions of bright (greater than 10(exp -11) ergs/cm(exp 2)s), hard (1 to 15 keV) x-ray sources to 5-10 arcsec, and to measure their size and structure in three energy bands down to 10 arcsec resolution. The scientific purpose of this specification was to enable the identification of these x-ray sources with optical and radio objects in order to elucidate the x-ray emission mechanism and the nature of the candidate astronomical system. The experiment was an outstanding success. Hardware systems functioned perfectly although loss of one (out of eight) proportional counters degraded our sensitivity by about 10 percent. Our aspect solution of 7 arcsec precision, allowed us to achieve statistic-limited location precision for all but the strongest sources. We vigorously pursued a strategy of determining the scientific importance of each identification, and of publishing each scientific result as it came along.

  12. How parrots talk: insights based on CT scans, image processing, and mathematical models

    NASA Astrophysics Data System (ADS)

    Patterson, Dianne K.; Pepperberg, Irene M.; Story, Brad H.; Hoffman, Eric A.

    1997-05-01

    Little is known about mechanisms of speech production in parrots. Recently, however, techniques for correlating vocal tract shape with vowel production in humans have become more sophisticated and we have adapted these techniques for use with parrots. We scanned two grey parrot heads with intact vocal tracts. One specimen, 'Oldbird' was fixed with its beak propped open; the second 'Youngbird' was fixed with its beak closed. Using VIDA software, we (1) established that differences in tongue and larynx positioning resulted from opening or closing the beak; and (2) obtained lengths and area functions for the trachea, glottis, pharynx, mouth, and choana for both specimens and esophageal length and area functions for the first specimen. We entered lengths and area functions into a 1D wave propagation model to determine the natural formant frequencies associated with an open versus closed beak. We also determined how manipulating lengths and area functions could affect formant frequency and relative intensity. Finally, by comparing observed grey parrot vowel formant, we predict how the parrot uses its vocal tract to produce speech.

  13. Image-based autonomous micromanipulation system for arrangement of spheres in a scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Kasaya, Takeshi; Miyazaki, Hideki T.; Saito, Shigeki; Koyano, Koichi; Yamaura, Tomio; Sato, Tomomasa

    2004-06-01

    The micromanipulation technique in a scanning electron microscope (SEM) has been attracting interest as a technique to produce microstructures such as three-dimensional photonic crystals or advanced high-density electronic circuits. However, it is difficult to fabricate a large-scale structure or to conduct a systematic experiment using numbers of structures, as long as we rely on manually operated micromanipulation. In this study, we constructed an automatic system which arranges 10-μm-sized microspheres into a given two-dimensional pattern in a SEM. The spheres are picked up by touching with the center of the planar tip of a probe (needle), and placed on the substrate by moving the contact point to the edge of the tip and inclining the probe. The positions of the probe and the spheres are visually recognized from the SEM image from above and the optical microscope image from the side. The generalized Hough transform, which can robustly detect arbitrary shape from the edge fragments, is employed for the image recognition. Contact force information obtained by a force sensor with a resolution of 14 μN is also utilized for the control. Completely automatic rearrangement of randomly sprinkled metal spheres with a diameter of 30 μm into arbitrary patterns was successfully demonstrated. Autonomous micromanipulation technique under the observation of a SEM would contribute not merely to laboratories but also to the opto-electronics industry.

  14. Assessment method of numerical integration used in measuring profile based on ultra-precise thin light beam scanning

    NASA Astrophysics Data System (ADS)

    Lang, Zhi-Guo; Tan, Jiu-Bin

    2009-11-01

    In order to improve the precision of profile measurement based on ultra-precise thin light beam scanning, an assessment method that compares different numerical integration algorithms in frequency-domain is put forward. The compared numerical integration methods are regarded as recursive digital filters. Through comparing their functions of frequency response in frequency-domain, the delivering role of noise with different frequencies can be analyzed directly and clearly in the process of integrating measured slope data. Analyzing results show that the method of cubic spline is better than trapezoidal, Simpson and 3/8 Simpson rules.

  15. Enhanced sensitivity of pHluorin-based monitoring of intracellular pH changes achieved through synchronously scanned fluorescence spectra.

    PubMed

    Plášek, Jaromír; Melcrová, Adéla; Gášková, Dana

    2015-10-06

    Since its introduction in 1998, genetically encoded pH-sensitive sensor ratiometric pHluorin proved to be a valuable tool for cell physiology studies. Here, we show how the sensitivity of pHluorin-based monitoring of intracellular pH changes performed with cell suspensions can be enhanced by using synchronously scanned fluorescence spectroscopy. In the suspensions of S. cerevisiae cells subjected to varying extracellular pH values, we have been able to measure statistically significant changes in intracellular pH of less than 0.1 unit, which were not detectable using a standard ratiometric approach.

  16. Analysis on the lateral resolution of optical scanning holography system based on random phase encoding using restricted pupils

    NASA Astrophysics Data System (ADS)

    Wang, Yun; Hu, Jian-Ping; Yuan, Sheng; Xie, Jian; Guo, Xue-Fan; Zhang, Luo-Zhi; Wan, Dao-Ming; Hu, You-Jun; Zhou, Xin

    2014-05-01

    In this paper, we analyze the point spread function of optical scanning holography (OSH) system based on random phase encoding (RPE-OSH) with restricted pupils and compare the lateral resolution of RPE-OSH system with the one of conventional OSH system by the definition of Rayleigh criterion. The results show that the main lobe width of RPE-OSH system is much narrower than that of the conventional OSH system under the same conditions; thus, the reconstructed image in RPE-OSH system has a higher lateral resolution and reserves more detailed information. This conclusion is verified by numerical simulations of the Cymbella cymbiformis image reconstruction.

  17. SU-E-I-37: Eye Lens Dose Reduction From CT Scan Using Organ Based Tube Current Modulation

    SciTech Connect

    Liu, H; Liu, T; Xu, X; Wu, J; Zhuo, W

    2015-06-15

    Purpose: To investigate the eye lens dose reduction by CT scan with organ based tube current modulation (OBTCM) using GPU Monte Carlo code ARCHER-CT. Methods: 36 X-ray sources and bowtie filters were placed around the patient head with the projection angle interval of 10° for one rotation of CT scan, each projection was simulated respectively. The voxel eye models with high resolution(0.1mm*0.1mm*0.1mm) were used in the simulation and different tube voltage including 80kVp, 100kVp, 120kVp and 140kVp were taken into consideration. Results: The radiation doses to the eye lens increased with the tube voltage raised from 80kVp to 140kVp, and the dose results from 0° (AP) direction are much higher than those from 180° (PA) direction for all the 4 different tube voltage investigated. This 360° projection dose characteristic enables organ based TCM, which can reduce the eye lens dose by more than 55%. Conclusion: As the eye lens belongs to superficial tissues, its radiation dose to external exposure like CT is direction sensitive, and this characteristic feature makes organ based TCM to be an effective way to reduce the eye lens dose, so more clinical use of this technique were recommended. National Nature Science Foundation of China(No.11475047)

  18. Gallium scan

    MedlinePlus

    ... material called gallium and is a type of nuclear medicine exam. A related test is gallium scan ... Brown ML, Forstrom LA, et al. Society of nuclear medicine procedure guideline for gallium scintigraphy in inflammation. ...

  19. CT Scan

    MedlinePlus

    ... exposing your baby to radiation. Reactions to contrast material In certain cases, your doctor may recommend you ... for a few hours before your scan Contrast material A special dye called a contrast material is ...

  20. Extracellular Control of Limb Regeneration

    NASA Astrophysics Data System (ADS)

    Calve, S.; Simon, H.-G.

    Adult newts possess the ability to completely regenerate organs and appendages. Immediately after limb loss, the extracellular matrix (ECM) undergoes dramatic changes that may provide mechanical and biochemical cues to guide the formation of the blastema, which is comprised of uncommitted stem-like cells that proliferate to replace the lost structure. Skeletal muscle is a known reservoir for blastema cells but the mechanism by which it contributes progenitor cells is still unclear. To create physiologically relevant culture conditions for the testing of primary newt muscle cells in vitro, the spatio-temporal distribution of ECM components and the mechanical properties of newt muscle were analyzed. Tenascin-C and hyaluronic acid (HA) were found to be dramatically upregulated in the amputated limb and were co-expressed around regenerating skeletal muscle. The transverse stiffness of muscle measured in situ was used as a guide to generate silicone-based substrates of physiological stiffness. Culturing newt muscle cells under different conditions revealed that the cells are sensitive to both matrix coating and substrate stiffness: Myoblasts on HA-coated soft substrates display a rounded morphology and become more elongated as the stiffness of the substrate increases. Coating of soft substrates with matrigel or fibronectin enhanced cell spreading and eventual cell fusion.

  1. Spot Scanning Proton Therapy for Malignancies of the Base of Skull: Treatment Planning, Acute Toxicities, and Preliminary Clinical Outcomes

    SciTech Connect

    Grosshans, David R.; Zhu, X. Ronald; Melancon, Adam; Allen, Pamela K.; Poenisch, Falk; Palmer, Matthew; McAleer, Mary Frances; McGovern, Susan L.; Gillin, Michael; DeMonte, Franco; Chang, Eric L.; Brown, Paul D.; Mahajan, Anita

    2014-11-01

    Purpose: To describe treatment planning techniques and early clinical outcomes in patients treated with spot scanning proton therapy for chordoma or chondrosarcoma of the skull base. Methods and Materials: From June 2010 through August 2011, 15 patients were treated with spot scanning proton therapy for chordoma (n=10) or chondrosarcoma (n=5) at a single institution. Toxicity was prospectively evaluated and scored weekly and at all follow-up visits according to Common Terminology Criteria for Adverse Events, version 3.0. Treatment planning techniques and dosimetric data were recorded and compared with those of passive scattering plans created with clinically applicable dose constraints. Results: Ten patients were treated with single-field-optimized scanning beam plans and 5 with multifield-optimized intensity modulated proton therapy. All but 2 patients received a simultaneous integrated boost as well. The mean prescribed radiation doses were 69.8 Gy (relative biological effectiveness [RBE]; range, 68-70 Gy [RBE]) for chordoma and 68.4 Gy (RBE) (range, 66-70) for chondrosarcoma. In comparison with passive scattering plans, spot scanning plans demonstrated improved high-dose conformality and sparing of temporal lobes and brainstem. Clinically, the most common acute toxicities included fatigue (grade 2 for 2 patients, grade 1 for 8 patients) and nausea (grade 2 for 2 patients, grade 1 for 6 patients). No toxicities of grades 3 to 5 were recorded. At a median follow-up time of 27 months (range, 13-42 months), 1 patient had experienced local recurrence and a second developed distant metastatic disease. Two patients had magnetic resonance imaging-documented temporal lobe changes, and a third patient developed facial numbness. No other subacute or late effects were recorded. Conclusions: In comparison to passive scattering, treatment plans for spot scanning proton therapy displayed improved high-dose conformality. Clinically, the treatment was well tolerated, and

  2. Analysis of classical guitars' vibrational behavior based on scanning laser vibrometer measurements

    NASA Astrophysics Data System (ADS)

    Czajkowska, Marzena

    2012-06-01

    One of the main goals in musical acoustics research is to link measurable, physical properties of a musical instrument with subjective assessments of its tone quality. The aim of the research discussed in this paper was to observe the structural vibrations of different class classical guitars in relation to their quality. This work focuses on mid-low-and low-class classical (nylon-stringed) guitars. The main source of guitar body vibrations come from top and back plate vibrations therefore these were the objects of structural mode measurements and analysis. Sixteen classical guitars have been investigated, nine with cedar and seven with spruce top plate. Structural modes of top and back plates have been measured with the aid of a scanning laser vibrometer and the instruments were excited with a chirp signal transferred by bone vibrator. The issues related to excitor selection have been discussed. Correlation and descriptive statistics of top and back plates measurement results have been investigated in relation to guitar quality. The frequency range of 300 Hz to 5 kHz as well as selected narrowed frequency bands have been analyzed for cedar and spruce guitars. Furthermore, the influence of top plate wood type on vibration characteristics have been observed on three pairs of guitars. The instruments were of the same model but different top plate material. Determination and visualization of both guitar plates' modal patterns in relation to frequency are a significant attainment of the research. Scanning laser vibrometer measurements allow particular mode observation and therefore mode identification, as opposed to sound pressure response measurements. When correlating vibration characteristics of top and back plates it appears that Pearson productmoment correlation coefficient is not a parameter that associates with guitar quality. However, for best instruments with cedar top, top-back correlation coefficient has relatively greater value in 1-2 kHz band and lower in

  3. Modeling Vehicle Collision Angle in Traffic Crashes Based on Three-Dimensional Laser Scanning Data

    PubMed Central

    Lyu, Nengchao; Huang, Gang; Wu, Chaozhong; Duan, Zhicheng; Li, Pingfan

    2017-01-01

    In road traffic accidents, the analysis of a vehicle’s collision angle plays a key role in identifying a traffic accident’s form and cause. However, because accurate estimation of vehicle collision angle involves many factors, it is difficult to accurately determine it in cases in which less physical evidence is available and there is a lack of monitoring. This paper establishes the mathematical relation model between collision angle, deformation, and normal vector in the collision region according to the equations of particle deformation and force in Hooke’s law of classical mechanics. At the same time, the surface reconstruction method suitable for a normal vector solution is studied. Finally, the estimation model of vehicle collision angle is presented. In order to verify the correctness of the model, verification of multi-angle collision experiments and sensitivity analysis of laser scanning precision for the angle have been carried out using three-dimensional (3D) data obtained by a 3D laser scanner in the collision deformation zone. Under the conditions with which the model has been defined, validation results show that the collision angle is a result of the weighted synthesis of the normal vector of the collision point and the weight value is the deformation of the collision point corresponding to normal vectors. These conclusions prove the applicability of the model. The collision angle model proposed in this paper can be used as the theoretical basis for traffic accident identification and cause analysis. It can also be used as a theoretical reference for the study of the impact deformation of elastic materials. PMID:28264517

  4. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope

    NASA Astrophysics Data System (ADS)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10-7 Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  5. Modeling Vehicle Collision Angle in Traffic Crashes Based on Three-Dimensional Laser Scanning Data.

    PubMed

    Lyu, Nengchao; Huang, Gang; Wu, Chaozhong; Duan, Zhicheng; Li, Pingfan

    2017-02-28

    In road traffic accidents, the analysis of a vehicle's collision angle plays a key role in identifying a traffic accident's form and cause. However, because accurate estimation of vehicle collision angle involves many factors, it is difficult to accurately determine it in cases in which less physical evidence is available and there is a lack of monitoring. This paper establishes the mathematical relation model between collision angle, deformation, and normal vector in the collision region according to the equations of particle deformation and force in Hooke's law of classical mechanics. At the same time, the surface reconstruction method suitable for a normal vector solution is studied. Finally, the estimation model of vehicle collision angle is presented. In order to verify the correctness of the model, verification of multi-angle collision experiments and sensitivity analysis of laser scanning precision for the angle have been carried out using three-dimensional (3D) data obtained by a 3D laser scanner in the collision deformation zone. Under the conditions with which the model has been defined, validation results show that the collision angle is a result of the weighted synthesis of the normal vector of the collision point and the weight value is the deformation of the collision point corresponding to normal vectors. These conclusions prove the applicability of the model. The collision angle model proposed in this paper can be used as the theoretical basis for traffic accident identification and cause analysis. It can also be used as a theoretical reference for the study of the impact deformation of elastic materials.

  6. FibroScan used in street-based outreach for drug users is useful for hepatitis C virus screening and management: a prospective study.

    PubMed

    Foucher, J; Reiller, B; Jullien, V; Léal, F; di Cesare, E S; Merrouche, W; Delile, J-M; de Lédinghen, V

    2009-02-01

    Although hepatitis C virus (HCV) infection prevalence is high among drug users, they do not commonly receive regular care in academic centres. The aim of this prospective study was to assess the influence of FibroScan use on HCV screening and management in street-based outreach. From January 2006 to January 2007, all consecutive drug users were offered noninvasive evaluation of liver fibrosis with FibroScan. After FibroScan, parameters were recorded with a structured, face-to-face questionnaire by outreach workers. All 298 subjects accepted FibroScan evaluation drug use was--ever injected heroin (69%), ever snorted or injected cocaine (89%), current chronic alcohol abuse (44%). The median FibroScan score was 5.3 kPa. Before blood sampling, 34% of subjects reported HCV positivity. HCV positivity was found in 83 cases. All these subjects had positive HCV-RNA. Forty-five subjects agreed to meet a hepatologist. By multivariate analysis, never snorted cocaine, consumed alcohol < 21 drinks per week, duration of injected heroin > 7 years, and FibroScan > 7.1 kPa were significantly associated with HCV positivity. Thus in a street-based outreach service for drug users, the acceptance of FibroScan is excellent. FibroScan with a hospital-based physician may facilitate screening and management of drug users for HCV infection.

  7. Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient

    PubMed Central

    Ortiz-Catalan, Max; Sander, Nichlas; Kristoffersen, Morten B.; Håkansson, Bo; Brånemark, Rickard

    2014-01-01

    A variety of treatments have been historically used to alleviate phantom limb pain (PLP) with varying efficacy. Recently, virtual reality (VR) has been employed as a more sophisticated mirror therapy. Despite the advantages of VR over a conventional mirror, this approach has retained the use of the contralateral limb and is therefore restricted to unilateral amputees. Moreover, this strategy disregards the actual effort made by the patient to produce phantom motions. In this work, we investigate a treatment in which the virtual limb responds directly to myoelectric activity at the stump, while the illusion of a restored limb is enhanced through augmented reality (AR). Further, phantom motions are facilitated and encouraged through gaming. The proposed set of technologies was administered to a chronic PLP patient who has shown resistance to a variety of treatments (including mirror therapy) for 48 years. Individual and simultaneous phantom movements were predicted using myoelectric pattern recognition and were then used as input for VR and AR environments, as well as for a racing game. The sustained level of pain reported by the patient was gradually reduced to complete pain-free periods. The phantom posture initially reported as a strongly closed fist was gradually relaxed, interestingly resembling the neutral posture displayed by the virtual limb. The patient acquired the ability to freely move his phantom limb, and a telescopic effect was observed where the position of the phantom hand was restored to the anatomically correct distance. More importantly, the effect of the interventions was positively and noticeably perceived by the patient and his relatives. Despite the limitation of a single case study, the successful results of the proposed system in a patient for whom other medical and non-medical treatments have been ineffective justifies and motivates further investigation in a wider study. PMID:24616655

  8. Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient.

    PubMed

    Ortiz-Catalan, Max; Sander, Nichlas; Kristoffersen, Morten B; Håkansson, Bo; Brånemark, Rickard

    2014-01-01

    A variety of treatments have been historically used to alleviate phantom limb pain (PLP) with varying efficacy. Recently, virtual reality (VR) has been employed as a more sophisticated mirror therapy. Despite the advantages of VR over a conventional mirror, this approach has retained the use of the contralateral limb and is therefore restricted to unilateral amputees. Moreover, this strategy disregards the actual effort made by the patient to produce phantom motions. In this work, we investigate a treatment in which the virtual limb responds directly to myoelectric activity at the stump, while the illusion of a restored limb is enhanced through augmented reality (AR). Further, phantom motions are facilitated and encouraged through gaming. The proposed set of technologies was administered to a chronic PLP patient who has shown resistance to a variety of treatments (including mirror therapy) for 48 years. Individual and simultaneous phantom movements were predicted using myoelectric pattern recognition and were then used as input for VR and AR environments, as well as for a racing game. The sustained level of pain reported by the patient was gradually reduced to complete pain-free periods. The phantom posture initially reported as a strongly closed fist was gradually relaxed, interestingly resembling the neutral posture displayed by the virtual limb. The patient acquired the ability to freely move his phantom limb, and a telescopic effect was observed where the position of the phantom hand was restored to the anatomically correct distance. More importantly, the effect of the interventions was positively and noticeably perceived by the patient and his relatives. Despite the limitation of a single case study, the successful results of the proposed system in a patient for whom other medical and non-medical treatments have been ineffective justifies and motivates further investigation in a wider study.

  9. Structured Light Based 3d Scanning for Specular Surface by the Combination of Gray Code and Phase Shifting

    NASA Astrophysics Data System (ADS)

    Zhang, Yujia; Yilmaz, Alper

    2016-06-01

    Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new

  10. Robot therapy of the upper limb in stroke patients: preliminary experiences for the principle-based use of this technology.

    PubMed

    Casadio, Maura; Giannoni, Psiche; Masia, Lorenzo; Morasso, Pietro; Sandini, Giulio; Sanguineti, Vittorio; Squeri, Valentina; Vergaro, Elena

    2009-01-01

    Robotic systems for neuromotor rehabilitation have been a part of clinical practice for more than a decade but the efficacy of this new technology is still debated. One reason for this, in our opinion, is that there is still no consensus on the most important features of these systems, or on the underlying theoretical basis, essential for the rational design of treatment protocols. The aim of this paper, born of our long experience in the study of the neural control of movement and the use of robots for characterizing motor control mechanisms, is to make a small contribution to clarifying this issue. What is needed in the future is a "research pipeline" encompassing experimentally validated models of neural control of movement, models of motor learning, models of functional recovery, and finally principle-based robot therapy control strategies. We believe this is a necessary prerequisite for carrying out well formulated comparisons of different control strategies as well as mixed strategies of robot/human treatment, in the framework of randomised, controlled clinical trials.

  11. Specialize or risk disappearance - empirical evidence of anisomerism based on comparative and developmental studies of gnathostome head and limb musculature.

    PubMed

    Diogo, Rui; Ziermann, Janine M; Linde-Medina, Marta

    2015-08-01

    William K. Gregory was one of the most influential authors defending the existence of an evolutionary trend in vertebrates from a higher degree of polyisomerism (more polyisomeric or 'serial' anatomical structures arranged along any body axis) to cases of anisomerism (specialization or loss of at least some original polyisomeric structures). Anisomerism was the subject of much interest during the 19th and the beginning of the 20th centuries, particularly due to the influence of the Romantic German School and the notion of 'primitive archetype' and because it was conceptually linked to other crucial biological issues (e.g. complexity, scala naturae, progress, modularity or phenotypic integration). However, discussions on anisomerism and related issues (e.g. Williston's law) have been almost exclusively based on hard tissues. Here we provide the first detailed empirical test, and discussion, of anisomerism based on quantitative data obtained from phylogenetic and comparative analyses of the head and forelimb muscles of gnathostomes. Our results strongly support the existence of such a trend in both forelimb and head musculature. For instance, the last common ancestor (LCA) of extant tetrapods likely had 38 polyisomeric muscles (PMs) out of a total of 70 forelimb muscles (i.e. 54%), whereas in the LCAs of extant amniotes and of mammals these numbers were 38/73 (52%) and 21/67 (31%), and in humans are 11/59 (19%). Interestingly, the number of PMs that became specialized during the forelimb evolutionary transition from the LCA of extant tetrapods to humans (13) is very similar to the number of PMs that became lost (14), indicating that both specialization and loss contributed equally to the trend towards anisomerism. By contrast, during the evolution of the head musculature from the LCA of gnathostomes to humans a total of 27 PMs were lost whereas only one muscle became specialized. Importantly, the evolutionary trend towards anisomerism is not related to a general

  12. The distribution of high altitude (70km) ice clouds in the Mars atmosphere from MGS TES limb radiance measurements

    NASA Astrophysics Data System (ADS)

    Clancy, T.; Wolff, M.

    One of the more interesting aspects of the atmospheric temperature profiles retrieved during the Pathfinder descent entry was the detection of cold 80km altitude temperatures below the saturation conditions for CO2 ice formation (Schofield et al., 1997). Disk average measurements of 70-80 km altitudes temperatures from ground-based sub-millimeter CO line observations are only 20K above CO2 saturation temperatures around the Mars Ls = 0 and 180 equinoctial seasons (Clancy, 1999). Clancy and Sandor (1998) suggested the relatively frequent occurrence of CO2 ice clouds in the 70-80 km altitude region, on the basis of the observed cold temperatures, Pathfinder images of blue (small size) ice clouds in the predawn sky, and Mariner 6 and 7 near-IR (4.3 micron) identification of CO2 ice in equatorial limb tangent views around Ls=200 in 1969 (Herr and Pimental, 1970). Before MGS observations, it remained unclear whether CO2 or water ice aerosols are ever present at >60km altitudes. Certainly dust aerosols had been identified at such high altitudes in Mariner 9 (Anderson and Leovy, 1978) and Viking (Jaquin et al., 1986) limb imaging, associated with the 1971 and 1977 global dust storms. The highest detached ice cloud identified from Viking limb data occurred at 55 km tangent altitude, at 16S, 72W and Ls = 176 (Jaquin et al., 1986; recently modeled by Montmessin et al., 2002). This seasonal period and location is actually fairly consistent with 70-80 km detached limb clouds that are observed prominently in the TES solarband limb scans, and appear restricted to fairly specific locations and seasons. The character of these high altitude limb clouds is displayed as a strong peak in scattered light is presented at 70-80 km altitudes, which is not resolved by the TES limb vertical resolution of ˜ 10 km and not detected in the coincident TES thermal IR spectral radiances. It is possible that co-adding of all limb IR spectra associated with TES solarband detections of these clouds

  13. Scanning Web-based ICARTT File Tool (SWIFT): an online tool used to validate ICARTT-formatted airborne science data

    NASA Astrophysics Data System (ADS)

    Lucker, P. L.; Mangosing, D. C.; Chen, G.; Rinsland, P.; Brennan, J. H.; Clodius, B. F.

    2011-12-01

    The ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) file format was recently endorsed by the NASA Earth Science Data Systems Standards Process Group (ESDS SPG) as a standard (ESDS-RFC-019) for specifying airborne-based Earth System Data Records (ESDR). In order to accelerate adoption of the new standard in the airborne science data community, SWIFT (Scanning Web-based ICARTT File Tool) was developed to provide a means for data providers to validate their own originated ICARTT-formatted file before submission to data archival facilities provided by NASA Langley's Atmospheric Science Data Center and the NASA Langley Airborne Science Data for Atmospheric Composition group. SWIFT builds upon a predecessor, a software utility named: FSCAN (File Scan). A major upgrade to FSCAN, the objective of SWIFT is to support all valid ICARTT files and to extract and store the file metadata in an ESDR relational database. The SWIFT-validated search metadata make it possible for COTS software and web applications to leverage the built-in spatial and temporal query capabilities of the relational database and to enable file and parameter sub-setting capabilities, as well as facilitating the generation of airborne science data merge products. These enhancements help to minimize development time of other related web applications and open up opportunities for robust data queries.

  14. Optical CT scanning of PRESAGETM polyurethane samples with a CCD-based readout system

    NASA Astrophysics Data System (ADS)

    Doran, S. J.; Krstajic, N.; Adamovics, J.; Jenneson, P. M.

    2004-01-01

    This article demonstrates the resolution capabilities of the CCD scanner under ideal circumstances and describes the first CCD-based optical CT experiments on a new class of dosimeter, known as PRESAGETM (Heuris Pharma, Skillman, NJ).

  15. Petrography of Permian "Gondwana" coals from boreholes in northwestern Bangladesh, based on semiautomated reflectance scanning

    USGS Publications Warehouse

    Bostick, N.H.; Betterton, W.J.; Gluskoter, H.J.; Nazrul, Islam M.

    1991-01-01

    Drilling through Quaternary alluvium and Tertiary cover at low-gravity anomalies in northwestern Bangladesh showed the presence of Permian sedimentary rocks in depressions that may be as much as a thousand meters deep in the crystalline basement. These Permian strata include low-sulfur, high-volatile bituminous coals in beds as thick as 15 m. The maceral group composition of these coals was determined by semiautomated reflectance scanning with a motorized microscope stage, rather than by point counting. This method was chosen to give objectively recorded raw analytical data and to provide a graphical picture of each sample. The coals are mostly "Gondwana" type (poorly layered "plum pudding" with abundant minerals and inertinite in a vitrinite groundmass) that would be classed as semi-dull (inerto-gelitite) coals. However, six samples have more than 70% vitrinite. None of the samples would be classed as sapropelic (liptinitic). The upper, middle, and lower main seams in borehole GDH-45 were sampled in 10 benches (0.1-3 m thick) each. Inertinite ranges from 7 to 100 vol% (mineral free basis) in individual benches, but composite seam averages are 41, 54 and 67%. Inertinite increases toward the top of two main seams so the bottom would yield the most valuable first mine slices. Some benches with extremely high inertinite content, such as the top 7 m of the lower thick seam, might be mined specially for blending with foreign low-inert coals to increase coke strength. The free swelling index reaches 7.5 in several vitrinite-rich benches, which can indicate good coking coal. Much of the vitrinite is fluorescent, which indicates secondary bituminization characteristic of vitrinite in good coking coals. Ash yields range from 8 to 52%, with composite seam averages of 15, 14 and 24%. Rare visible pyrite is in veinlets or small nodules; framboids and dispersed pyrite are absent. In borehole GDH-40 near Barapukuria (200-500 m depth), the mean random reflectance of vitrinite "A

  16. Motor Impairment Evaluation for Upper Limb in Stroke Patients on the Basis of a Microsensor

    ERIC Educational Resources Information Center

    Huang, Shuai; Luo, Chun; Ye, Shiwei; Liu, Fei; Xie, Bin; Wang, Caifeng; Yang, Li; Huang, Zhen; Wu, Jiankang

    2012-01-01

    There has been an urgent need for an effective and efficient upper limb rehabilitation method for poststroke patients. We present a Micro-Sensor-based Upper Limb rehabilitation System for poststroke patients. The wearable motion capture units are attached to upper limb segments embedded in the fabric of garments. The body segment orientation…

  17. The Nimbus 7 LIMS (Limb Infrared Monitor of the Stratosphere) water vapor measurements

    NASA Astrophysics Data System (ADS)

    Remsberg, Ellis E.; Russell, James M., III

    Earth orbital instruments, designed to measure the vertical and spatial distribution of atmospheric water vapor is discussed. Specifically, the operation of the Limb Infrared Monitor of the Stratosphere (LIMS) experiment is examined. The LIMS is a six channel limb scanning radiometer that was launched aboard Nimbus 7 in 1978. Profiles of stratospheric and mesospheric temperature, water vapor, and various other constituents were obtained by inverting the LIMS radiance measurements. This same technique was used in 1981 to analyze the data returned from another limb scanning radiometer aboard the Solar Mesosphere Explorer.

  18. Side scan sonar image segmentation based on neutrosophic set and quantum-behaved particle swarm optimization algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, Jianhu; Wang, Xiao; Zhang, Hongmei; Hu, Jun; Jian, Xiaomin

    2016-09-01

    To fulfill side scan sonar (SSS) image segmentation accurately and efficiently, a novel segmentation algorithm based on neutrosophic set (NS) and quantum-behaved particle swarm optimization (QPSO) is proposed in this paper. Firstly, the neutrosophic subset images are obtained by transforming the input image into the NS domain. Then, a co-occurrence matrix is accurately constructed based on these subset images, and the entropy of the gray level image is described to serve as the fitness function of the QPSO algorithm. Moreover, the optimal two-dimensional segmentation threshold vector is quickly obtained by QPSO. Finally, the contours of the interested target are segmented with the threshold vector and extracted by the mathematic morphology operation. To further improve the segmentation efficiency, the single threshold segmentation, an alternative algorithm, is recommended for the shadow segmentation by considering the gray level characteristics of the shadow. The accuracy and efficiency of the proposed algorithm are assessed with experiments of SSS image segmentation.

  19. Limb lengthening in achondroplasia

    PubMed Central

    Chilbule, Sanjay K; Dutt, Vivek; Madhuri, Vrisha

    2016-01-01

    Background: Stature lengthening in skeletal dysplasia is a contentious issue. Specific guidelines regarding the age and sequence of surgery, methods and extent of lengthening at each stage are not uniform around the world. Despite the need for multiple surgeries, with their attendant complications, parents demanding stature lengthening are not rare, due to the social bias and psychological effects experienced by these patients. This study describes the outcome and complications of extensive stature lengthening performed at our center. Materials and Methods: Eight achondroplasic and one hypochondroplasic patient underwent bilateral transverse lengthening for tibiae, humeri and femora. Tibia lengthening was carried out using a ring fixator and bifocal corticotomy, while a monolateral pediatric limb reconstruction system with unifocal corticotomy was used for the femur and humerus. Lengthening of each bone segment, height gain, healing index and complications were assessed. Subgroup analysis was carried out to assess the effect of age and bone segment on the healing index. Results: Nine patients aged five to 25 years (mean age 10.2 years) underwent limb lengthening procedures for 18 tibiae, 10 femora and 8 humeri. Four patients underwent bilateral lengthening of all three segments. The mean length gain for the tibia, femur and humerus was 15.4 cm (100.7%), 9.9 cm (52.8%) and 9.6 cm (77.9%), respectively. Healing index was 25.7, 25.6 and 20.6 days/cm, respectively, for the tibia, femur and humerus. An average of 33.3% height gain was attained. Lengthening of both tibia and femur added to projected height achieved as the 3rd percentile of standard height in three out of four patients. In all, 33 complications were encountered (0.9 complications per segment). Healing index was not affected by age or bone segment. Conclusion: Extensive limb lengthening (more than 50% over initial length) carries significant risk and should be undertaken only after due consideration. PMID

  20. Airborne laser scanning based quantification of dead-ice melting in recently deglaciated terrain

    NASA Astrophysics Data System (ADS)

    Klug, C.; Sailer, R.; Schümberg, M.; Stötter, J.

    2012-04-01

    Dead-ice is explained as stagnant glacial ice, not influenced by glacier flow anymore. Whenever glaciers have negative mass balances and an accumulation of debris-cover on the surface, dead-ice may form. Although, there are numerous conceptual process-sediment-landform models for the melt-out of dead-ice bodies and areas of dead-ice environments at glacier margins are easily accessible, just a few quantitative studies of dead-ice melting have been carried out so far. Processes and rates of dead-ice melting are commonly believed to be controlled by climate and debris-cover properties, but there is still a lack of knowledge about this fact. This study has a focus on the quantification of process induced volumetric changes caused by dead-ice melting. The research for this project was conducted at Hintereisferner (Ötztal Alps, Austria), Gepatschferner (Ötztal Alps, Austria) and Schrankar (Stubai Alps, Austria), areas for which a good data basis of ALS (Airborne Laser Scanning) measurements is available. 'Hintereisferner' can be characterized as a typical high alpine environment in mid-latitudes, which ranges between approximately 2250 m and 3740 m a.s.l.. The Hintereisferner region has been investigated intensively since many decades. Two dead ice bodies at the orographic right side and one at the orographic left side of the Hintereisferner glacier terminus (approx. at 2500 m to 2550 m a.s.l.) were identified. Since 2001, ALS measurements have been carried out regularly at Hintereisferner resulting in a unique data record of 21 ALS flight campaigns, allowing long-term explorations of the two dead-ice areas. The second study area of 'Gepatschferner' in the Kaunertal ranges between 2060 m and 3520 m a.s.l. and is the second largest glacier of Austria. Near the glacier tongue at the orographic right side a significant dead ice body has formed. The ALS data used for quantification include a period of time of 4 years (2006 - 2010). 'Schrankar' is located in the Western

  1. Short-Term Memory Scanning Viewed as Exemplar-Based Categorization

    ERIC Educational Resources Information Center

    Nosofsky, Robert M.; Little, Daniel R.; Donkin, Christopher; Fific, Mario

    2011-01-01

    Exemplar-similarity models such as the exemplar-based random walk (EBRW) model (Nosofsky & Palmeri, 1997b) were designed to provide a formal account of multidimensional classification choice probabilities and response times (RTs). At the same time, a recurring theme has been to use exemplar models to account for old-new item recognition and to…

  2. Photothermal imaging scanning microscopy

    DOEpatents

    Chinn, Diane; Stolz, Christopher J.; Wu, Zhouling; Huber, Robert; Weinzapfel, Carolyn

    2006-07-11

    Photothermal Imaging Scanning Microscopy produces a rapid, thermal-based, non-destructive characterization apparatus. Also, a photothermal characterization method of surface and subsurface features includes micron and nanoscale spatial resolution of meter-sized optical materials.

  3. Multi-atlas-based segmentation with local decision fusion--application to cardiac and aortic segmentation in CT scans.

    PubMed

    Isgum, Ivana; Staring, Marius; Rutten, Annemarieke; Prokop, Mathias; Viergever, Max A; van Ginneken, Bram

    2009-07-01

    A novel atlas-based segmentation approach based on the combination of multiple registrations is presented. Multiple atlases are registered to a target image. To obtain a segmentation of the target, labels of the atlas images are propagated to it. The propagated labels are combined by spatially varying decision fusion weights. These weights are derived from local assessment of the registration success. Furthermore, an atlas selection procedure is proposed that is equivalent to sequential forward selection from statistical pattern recognition theory. The proposed method is compared to three existing atlas-based segmentation approaches, namely 1) single atlas-based segmentation, 2) average-shape atlas-based segmentation, and 3) multi-atlas-based segmentation with averaging as decision fusion. These methods were tested on the segmentation of the heart and the aorta in computed tomography scans of the thorax. The results show that the proposed method outperforms other methods and yields results very close to those of an independent human observer. Moreover, the additional atlas selection step led to a faster segmentation at a comparable performance.

  4. Additivity in perception of affect from limb motion.

    PubMed

    Etemad, S Ali; Arya, Ali; Parush, Avi

    2014-01-13

    In this study, the notion of additivity in perception of affect from limb motion is investigated. Specifically, we examine whether the impact of multiple limbs in perception of affect is equal to the sum of the impacts of each individual limb. Several neutral, happy, and sad walking sequences are first aligned and averaged. Four distinct body regions or limbs are defined for this study: arms and hands, legs and feet, head and neck, and torso. The three average walks are used to create the stimuli. The motion of each limb and combination of limbs from the neutral sequence are replaced with those of the happy and sad sequences. Through collecting perceptual ratings for when individual limbs contain affective features, and comparing the sums of these ratings to instances where multiple limbs of the body simultaneously contain affective features, additivity is investigated. We find that while the results are highly correlated, additivity does not hold in the classical sense. Based on the results, a mathematical model is proposed for describing the observed relationship.

  5. Laser Scanning Based Growth Analysis of Plants as a New Challenge for Deformation Monitoring

    NASA Astrophysics Data System (ADS)

    Dupuis, Jan; Holst, Christoph; Kuhlmann, Heiner

    2016-03-01

    Nowadays, the areal deformation analysis has become an important task in engineering geodesy. Thereby, not only manmade objects are of high interest, also natural objects, like plant organs, are focused more frequently. Thus, the analysis of leaf growth, i. e. the spatial development of the leaf surface, can be seen as a problem of deformation monitoring. In contrast to classical geodetic tasks, the absolute size of the deformation of the leaf surface is small, but usually great compared to the object size. Due to the optical characteristics of leaf surfaces, the point clouds, commonly acquired with high precision close-up laser scanners, provide a point-to-point distance that is small or equal compared to the measurement accuracy. Thus, the point clouds are usually processed and the leaf area is derived from a triangulation-based surface representation (mesh), resulting in a significant uncertainty of area calculation. In this paper, we illustrate the lacks of the mesh-based leaf area calculation. Using high precision gauge blocks as well as a number of tomato leaves, uncertainties of the area derivation are revealed and evaluated. The application of a B-spline approximation illustrates the advantages of an approximation-based approach and introduces the prospect for further research.

  6. The Measurements of Water Flow Rate in the T-shape Microchannels Based on the Scanning Micro-PIV Technique

    NASA Astrophysics Data System (ADS)

    Han, W.; Wang, H. L.; Xu, M.

    2011-09-01

    In this study, the scanning microfluidic particle image velocimetry (scanning micro-PIV) technique is used to measure the water flow rate in a T-shape microchannel with the inlet and outlet width being 300 μm and 200 μm, respectively. The standard flow rates controlled by the syringe pump are ranging from 3.508 to 11.693 μL/min. The quasi-three-dimensional velocities at the branch point of the T-shape microchannel are constructed by measuring the two-dimensional velocities on 11 fluid layers from the bottom of microchannel to the top. Based on this, the flow rates are calculated by the discrete integration of velocity distributions on the cross-section of microchannel. The relative errors of the flow rates of the inlet and outlet are all within 3%, and we conclude that the main factors affecting the measurement precision of flow rate include the wall roughness of the microchannel, the spatial resolution of microscopic system and the algorithm of velocity evaluation.

  7. Staging of Fatty Liver Diseases Based on Hierarchical Classification and Feature Fusion for Back-Scan-Converted Ultrasound Images.

    PubMed

    Owjimehr, Mehri; Danyali, Habibollah; Helfroush, Mohammad Sadegh; Shakibafard, Alireza

    2017-03-01

    Fatty liver disease is progressive and may not cause any symptoms at early stages. This disease is potentially fatal and can cause liver cancer in severe stages. Therefore, diagnosing and staging fatty liver disease in early stages is necessary. In this paper, a novel method is presented to classify normal and fatty liver, as well as discriminate three stages of fatty liver in ultrasound images. This study is performed with 129 subjects including 28 normal, 47 steatosis, 42 fibrosis, and 12 cirrhosis images. The proposed approach uses back-scan conversion of ultrasound sector images and is based on a hierarchical classification. The proposed algorithm is performed in two parts. The first part selects the optimum regions of interest from the focal zone of the back-scan-converted ultrasound images. In the second part, discrimination between normal and fatty liver is performed and then steatosis, fibrosis, and cirrhosis are classified in a hierarchical basis. The wavelet packet transform and gray-level co-occurrence matrix are used to obtain a number of statistical features. A support vector machine classifier is used to discriminate between normal and fatty liver, and stage fatty cases. The results of the proposed scheme clearly illustrate the efficiency of this system with overall accuracy of 94.91% and also specificity of more than 90%.

  8. Immobilization of zebrafish larvae on a chip-based device for environmental scanning electron microscopy (ESEM) imaging

    NASA Astrophysics Data System (ADS)

    Akagi, Jin; Hall, Chris J.; Crosier, Kathryn E.; Crosier, Philip S.; Wlodkowic, Donald

    2013-12-01

    Small vertebrate model organisms have recently gained popularity as attractive experimental models that enhance our understanding of human tissue and organ development. Laser microsurgery on zebrafish larvae combined with Scanning Electron Microscopy (SEM) imaging can in particular provide accelerated insights into the tissue regeneration phenomena. Conventional SEM exposes, however, specimens to high vacuum environments, and often requires laborintensive and time-consuming pretreatments and manual positioning. Moreover, there are virtually no technologies available that can quickly immobilize the zebrafish larvae for high definition SEM imaging. This work describes the proof-of-concept design and validation of a microfluidic chip-based system for immobilizing zebrafish larvae and it's interfacing with Environmental Scanning Electron Microscope (ESEM) imaging. The Lab-on-a-Chip (LOC) device was fabricated using a high-speed infrared laser micromachining and consists of a reservoir with multiple semispherical microwells, which hold the yolk of zebrafish larvae, and drain channels that allow removing excess of medium during SEM imaging. Paper filter is used to actuate the chip and immobilization of the larvae by gentle suction that occurs during water drainage. The trapping region allows multiple specimens to be positioned on the chip. The device is then inserted directly inside the ESEM and imaged in a near 100% humidity atmosphere. This facilitates ESEM imaging of untreated biological samples.

  9. Superhelix dimensions of a 1868 base pair plasmid determined by scanning force microscopy in air and in aqueous solution.

    PubMed Central

    Rippe, K; Mücke, N; Langowski, J

    1997-01-01

    We have used scanning force microscopy (SFM) to study the conformation of a 1868 base pair plasmid (p1868) in its open circular form and at a superhelical density of sigma= -0.034. The samples were deposited on a mica surface in the presence of MgCl2. DNA images were obtained both in air and in aqueous solutions, and the dimensions of the DNA superhelix were analysed. Evaluation of the whole plasmid yielded average superhelix dimensions of 27 +/- 9 nm (outer superhelix diameter D), 107 +/- 51 nm (superhelix pitch P), and 54 +/-8 degrees (superhelix pitch angle alpha). We also analysed compact superhelical regions within the plasmid separately, and determined values of D = 9.2 +/- 3.3 nm, P = 42 +/- 13 nm and alpha= 63 +/- 20 degrees for samples scanned in air or rehydrated in water. These results indicate relatively large conformation changes between superhelical and more open regions of the plasmid. In addition to the analysis of the DNA superhelix dimensions, we have followed the deposition process of open circular p1868 to mica in real time. These experiments show that it is possible to image DNA samples by SFM without prior drying, and that the surface bound DNA molecules retain some ability to change their position on the surface. PMID:9108155

  10. Comparing terrestrial laser scanning with ground and UAV-based imaging for national-level assessment of upland soil erosion

    NASA Astrophysics Data System (ADS)

    McShane, Gareth; Farrow, Luke; Morgan, David; Glendell, Miriam; James, Mike; Quinton, John; Evans, Martin; Anderson, Karen; Rawlins, Barry; Quine, Timothy; Debell, Leon; Benaud, Pia; Jones, Lee; Kirkham, Matthew; Lark, Murray; Rickson, Jane; Brazier, Richard

    2015-04-01

    Quantifying soil loss through erosion processes at a high resolution can be a time consuming and costly undertaking. In this pilot study 'a cost effective framework for monitoring soil erosion in England and Wales', funded by the UK Department for Environment, Food and Rural Affairs (Defra), we compare methods for collecting suitable topographic measurements via remote sensing. The aim is to enable efficient but detailed site-scale studies of erosion forms in inaccessible UK upland environments, to quantify dynamic processes, such as erosion and mass movement. The techniques assessed are terrestrial laser scanning (TLS), and unmanned aerial vehicle (UAV) photography and ground-based photography, both processed using structure-from-motion (SfM) 3D reconstruction software. Compared to other established techniques, such as expensive TLS, SfM offers a potentially low-cost alternative for the reconstruction of 3D high-resolution micro-topographic models from photographs taken with consumer grade cameras. However, whilst an increasing number of research papers examine the relative merits of these novel versus more established survey techniques, no study to date has compared both ground-based and aerial SfM photogrammetry with TLS scanning across a range of scales (from m2 to 16ha). The evaluation of these novel low cost techniques is particularly relevant in upland landscapes, where the remoteness and inaccessibility of field sites may render some of the more established survey techniques impractical. Volumetric estimates of soil loss are quantified using the digital surface models (DSMs) derived from the data from each technique and subtracted from a modelled pre-erosion surface. The results from each technique are compared. The UAV was able to capture information over a wide area, a range of altitudes and angles over the study area. Combined with automated SfM-based processing, this technique was able to produce rapid orthophotos to support ground-based data

  11. Application of a static fluorescence-based cytometer (the CellScan) in basic cytometric studies, clinical pharmacology, oncology and clinical immunology.

    PubMed

    Harel, Michal; Gilburd, Boris; Schiffenbauer, Yael S; Shoenfeld, Yehuda

    2005-09-01

    The CellScan apparatus is a laser scanning cytometer enabling repetitive fluorescence intensity (FI) and polarization (FP) measurements in living cells, as a means of monitoring lymphocyte activation. The CellScan may serve as a tool for diagnosis of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) as well as other autoimmune diseases by monitoring FP changes in peripheral blood lymphocytes (PBLs) following exposure to autoantigenic stimuli. Changes in FI and FP in atherosclerotic patients' PBLs following exposure to various stimuli have established the role of the immune system in atherosclerotic disease. The CellScan has been evaluated as a diagnostic tool for drug-allergy, based on FP reduction in PBLs following incubation with allergenic drugs. FI and FP changes in cancer cells have been found to be well correlated with the cytotoxic effect of anti-neoplastic drugs. In conclusion, the CellScan has a variety of applications in cell biology, immunology, cancer research and clinical pharmacology.

  12. Vasospastic Limb Ischemia Presenting Acute and Chronic Limb Ischemia

    PubMed Central

    2014-01-01

    Vasospastic limb ischemia might have been underappreciated compared to vasospasm in other territories such as heart and brain. However, an increasing awareness of this vascular disorder can be translated to an improved patients’ care. Herein, we report a case of vasospasm presenting acute and chronic limb ischemia in four extremities. PMID:24995065

  13. LIMB Demonstration Project Extension

    SciTech Connect

    Not Available

    1989-08-15

    The subject of this report is progress during the quarter for Phase I -- Design and Permitting, Phase II -- Coolside/LIMB Construction, Start-Up and Phase III -- Operation, Data Collection, Reporting and Disposition. Under Phase I, Task 2, Consol Technology Transfer, Consol R D continued to review the status of the Coolside installation and identified construction details which required additional action. Activities in Task 4.0 -- Permitting and Licensing have focused on finalizing a subcontract agreement for trucking the DOE Coolside/LIMB ash to a solid waste landfill. Under Phase II, Task 1, Project Management, purchase orders were placed with two (2) lime suppliers for supplying the specified hydrated lime to be used for the Coolside test program. For Subtask 2.2 -- Sorbent Feed System Installation, the construction and installation of the sorbent feed system has been completed. Under Phase III, Subtask 2.1, Optimization of the Coolside sorbent feed system, the ash recycle system and the caustic injection system were initiated. 3 figs.

  14. LDTK: Limb Darkening Toolkit

    NASA Astrophysics Data System (ADS)

    Parviainen, H.; Aigrain, S.

    2015-11-01

    We present a PYTHON package LDTK that automates the calculation of custom stellar limb-darkening (LD) profiles and model-specific limb-darkening coefficients using the library of PHOENIX-generated specific intensity spectra by Husser et al. The aim of the package is to facilitate analyses requiring custom generated LD profiles, such as the studies of exoplanet transits - especially transmission spectroscopy, where the transit modelling is carried out for custom narrow passbands - eclipsing binaries, interferometry, and microlensing events. First, LDTK can be used to compute custom LD profiles with uncertainties propagated from the uncertainties in the stellar parameter estimates. Secondly, LDTK can be used to estimate the LD-model-specific coefficients with uncertainties for the most common LD models. Thirdly, LDTK can be directly integrated into the log posterior computation of any pre-existing modelling code with minimal modifications. The last approach can be used to constrain the LD model parameter space directly by the LD profile, allowing for the marginalization over the LD parameter space without the need to approximate the constraint from the LD profile using a prior.

  15. Bone scanning in otolaryngology.

    PubMed

    Noyek, A M

    1979-09-01

    Modern radionuclide bone scanning has introduced a new concept in physiologic and anatomic diagnostic imaging to general medicine. As otolaryngologists must diagnose and treat disease in relation to the bony and/or cartilaginous supporting structures of the neurocranium and upper airway, this modality should be included in the otolaryngologist's diagnostic armamentarium. It is the purpose of this manuscript to study the specific applications of bone scanning to our specialty at this time, based on clinical experience over the past three years. This thesis describes the development of bone scanning in general (history of nuclear medicine and nuclear physics; history of bone scanning in particular). General concepts in nuclear medicine are then presented; these include a discussion of nuclear semantics, principles of radioactive emmissions, the properties 99mTc as a radionuclide, and the tracer principle. On the basis of these general concepts, specific concepts in bone scanning are then brought forth. The physiology of bone and the action of the bone scan agents is presented. Further discussion considers the availability and production of the bone scan agent, patient factors, the gamma camera, the triphasic bone scan and the ultimate diagnostic principle of the bone scan. Clinical applications of bone scanning in otolaryngology are then presented in three sections. Proven areas of application include the evaluation of malignant tumors of the head and neck, the diagnosis of temporomandibular joint disorders, the diagnosis of facial fractures, the evaluation of osteomyelitis, nuclear medicine imaging of the larynx, and the assessment of systemic disease. Areas of adjunctive or supplementary value are also noted, such as diagnostic imaging of meningioma. Finally, areas of marginal value in the application of bone scanning are described.

  16. Design and Optimization of an EEG-Based Brain Machine Interface (BMI) to an Upper-Limb Exoskeleton for Stroke Survivors.

    PubMed

    Bhagat, Nikunj A; Venkatakrishnan, Anusha; Abibullaev, Berdakh; Artz, Edward J; Yozbatiran, Nuray; Blank, Amy A; French, James; Karmonik, Christof; Grossman, Robert G; O'Malley, Marcia K; Francisco, Gerard E; Contreras-Vidal, Jose L

    2016-01-01

    This study demonstrates the feasibility of detecting motor intent from brain activity of chronic stroke patients using an asynchronous electroencephalography (EEG)-based brain machine interface (BMI). Intent was inferred from movement related cortical potentials (MRCPs) measured over an optimized set of EEG electrodes. Successful intent detection triggered the motion of an upper-limb exoskeleton (MAHI Exo-II), to guide movement and to encourage active user participation by providing instantaneous sensory feedback. Several BMI design features were optimized to increase system performance in the presence of single-trial variability of MRCPs in the injured brain: (1) an adaptive time window was used for extracting features during BMI calibration; (2) training data from two consecutive days were pooled for BMI calibration to increase robustness to handle the day-to-day variations typical of EEG, and (3) BMI predictions were gated by residual electromyography (EMG) activity from the impaired arm, to reduce the number of false positives. This patient-specific BMI calibration approach can accommodate a broad spectrum of stroke patients with diverse motor capabilities. Following BMI optimization on day 3, testing of the closed-loop BMI-MAHI exoskeleton, on 4th and 5th days of the study, showed consistent BMI performance with overall mean true positive rate (TPR) = 62.7 ± 21.4% on day 4 and 67.1 ± 14.6% on day 5. The overall false positive rate (FPR) across subjects was 27.74 ± 37.46% on day 4 and 27.5 ± 35.64% on day 5; however for two subjects who had residual motor function and could benefit from the EMG-gated BMI, the mean FPR was quite low (< 10%). On average, motor intent was detected -367 ± 328 ms before movement onset during closed-loop operation. These findings provide evidence that closed-loop EEG-based BMI for stroke patients can be designed and optimized to perform well across multiple days without system recalibration.

  17. Design and Optimization of an EEG-Based Brain Machine Interface (BMI) to an Upper-Limb Exoskeleton for Stroke Survivors

    PubMed Central

    Bhagat, Nikunj A.; Venkatakrishnan, Anusha; Abibullaev, Berdakh; Artz, Edward J.; Yozbatiran, Nuray; Blank, Amy A.; French, James; Karmonik, Christof; Grossman, Robert G.; O'Malley, Marcia K.; Francisco, Gerard E.; Contreras-Vidal, Jose L.

    2016-01-01

    This study demonstrates the feasibility of detecting motor intent from brain activity of chronic stroke patients using an asynchronous electroencephalography (EEG)-based brain machine interface (BMI). Intent was inferred from movement related cortical potentials (MRCPs) measured over an optimized set of EEG electrodes. Successful intent detection triggered the motion of an upper-limb exoskeleton (MAHI Exo-II), to guide movement and to encourage active user participation by providing instantaneous sensory feedback. Several BMI design features were optimized to increase system performance in the presence of single-trial variability of MRCPs in the injured brain: (1) an adaptive time window was used for extracting features during BMI calibration; (2) training data from two consecutive days were pooled for BMI calibration to increase robustness to handle the day-to-day variations typical of EEG, and (3) BMI predictions were gated by residual electromyography (EMG) activity from the impaired arm, to reduce the number of false positives. This patient-specific BMI calibration approach can accommodate a broad spectrum of stroke patients with diverse motor capabilities. Following BMI optimization on day 3, testing of the closed-loop BMI-MAHI exoskeleton, on 4th and 5th days of the study, showed consistent BMI performance with overall mean true positive rate (TPR) = 62.7 ± 21.4% on day 4 and 67.1 ± 14.6% on day 5. The overall false positive rate (FPR) across subjects was 27.74 ± 37.46% on day 4 and 27.5 ± 35.64% on day 5; however for two subjects who had residual motor function and could benefit from the EMG-gated BMI, the mean FPR was quite low (< 10%). On average, motor intent was detected −367 ± 328 ms before movement onset during closed-loop operation. These findings provide evidence that closed-loop EEG-based BMI for stroke patients can be designed and optimized to perform well across multiple days without system recalibration. PMID:27065787

  18. Nondestructive testing based on scanning-from-heating approach: application to nonthrough defect detection and fiber orientation assessment

    NASA Astrophysics Data System (ADS)

    Belkacemi, Mohamed; Stolz, Christophe; Mathieu, Alexandre; Lemaitre, Guillaume; Massich, Joan; Aubreton, Olivier

    2015-11-01

    Today, industries ensure the quality of their manufactured products through computer vision techniques and nonconventional imaging. Three-dimensional (3-D) scanners and nondestructive testing (NDT) systems are commonly used independently for such applications. Furthermore, these approaches combined constitute hybrid systems, providing a 3-D reconstruction and NDT analysis. These systems, however, suffer from drawbacks such as errors during the data fusion and higher cost for manufacturers. In an attempt to solve these problems, a single active thermography system based on scanning-from-heating is proposed in this paper. In addition to 3-D digitization of the object, our contributions are twofold: (1) the nonthrough defect detection for a homogeneous metallic object and (2) fiber orientation assessment for a long fiber composite material. The experiments on steel and aluminum plates show that our method achieves the detection of nonthrough defects. Additionally, the estimation of the fiber orientation is evaluated on carbon-fiber composite material.

  19. 3D imaging of cement-based materials at submicron resolution by combining laser scanning confocal microscopy with serial sectioning.

    PubMed

    Yio, M H N; Mac, M J; Wong, H S; Buenfeld, N R

    2015-05-01

    In this paper, we present a new method to reconstruct large volumes of nontransparent porous materials at submicron resolution. The proposed method combines fluorescence laser scanning confocal microscopy with serial sectioning to produce a series of overlapping confocal z-stacks, which are then aligned and stitched based on phase correlation. The method can be extended in the XY plane to further increase the overall image volume. Resolution of the reconstructed image volume does not degrade with increase in sample size. We have used the method to image cementitious materials, hardened cement paste and concrete and the results obtained show that the method is reliable. Possible applications of the method such as three-dimensional characterization of the pores and microcracks in hardened concrete, three-dimensional particle shape characterization of cementitious materials and three-dimensional characterization of other porous materials such as rocks and bioceramics are discussed.

  20. Detection of beta-amyloid (1-42) on protein array based on electrical detection technique using scanning tunneling microscopy.

    PubMed

    Choi, Jeong-Woo; Islam, A T M Kamrul; Lee, Jin-Ho; Song, Joon Myong; Oh, Byung-Keun

    2011-05-01

    In this study an immuno-array for Abeta42 based on scanning tunneling microscopy (STM) was developed using conjugated gold nanoparticle (Au-NP) and antibody (Ab) complex. Fragmented monoclonal Ab against Abeta42 was allowed to immobilize on the Au-dot arrays followed by its target protein Abeta42 and Au NP and Ab complex. The surface structure of Au-NP and Ab complex on Au-dots was investigated with Atomic Force Microscopy and the current profile of fabricated immunosensing element was investigated with STM. The power spectrum derived from the current profile was found to be increasing with higher concentrations of Abeta42 having a detection limit of 100 fg/ml. The proposed technique can be a promising method to construct the highly sensitive and efficient protein chip of immunosensors arrays.

  1. High-angle annular dark field scanning transmission electron microscopy on carbon-based functional polymer systems.

    PubMed

    Sourty, Erwan; van Bavel, Svetlana; Lu, Kangbo; Guerra, Ralph; Bar, Georg; Loos, Joachim

    2009-06-01

    Two purely carbon-based functional polymer systems were investigated by bright-field conventional transmission electron microscopy (CTEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). For a carbon black (CB) filled polymer system, HAADF-STEM provides high contrast between the CB agglomerates and the polymer matrix so that details of the interface organization easily can be revealed and assignment of the CB phase is straightforward. For a second system, the functional polymer blend representing the photoactive layer of a polymer solar cell, details of its nanoscale organization could be observed that were not accessible with CTEM. By varying the camera length in HAADF-STEM imaging, the contrast can be enhanced between crystalline and amorphous compounds due to diffraction contrast so that nanoscale interconnections between domains are identified. In general, due to its incoherent imaging characteristics HAADF-STEM allows for reliable interpretation of the data obtained.

  2. Software-based data path for raster-scanned multi-beam mask lithography

    NASA Astrophysics Data System (ADS)

    Rajagopalan, Archana; Agarwal, Ankita; Buck, Peter; Geller, Paul; Hamaker, H. Christopher; Rao, Nagswara

    2016-10-01

    According to the 2013 SEMATECH Mask Industry Survey,i roughly half of all photomasks are produced using laser mask pattern generator ("LMPG") lithography. LMPG lithography can be used for all layers at mature technology nodes, and for many non-critical and semi-critical masks at advanced nodes. The extensive use of multi-patterning at the 14-nm node significantly increases the number of critical mask layers, and the transition in wafer lithography from positive tone resist to negative tone resist at the 14-nm design node enables the switch from advanced binary masks back to attenuated phase shifting masks that require second level writes to remove unwanted chrome. LMPG lithography is typically used for second level writes due to its high productivity, absence of charging effects, and versatile non-actinic alignment capability. As multi-patterning use expands from double to triple patterning and beyond, the number of LMPG second level writes increases correspondingly. The desire to reserve the limited capacity of advanced electron beam writers for use when essential is another factor driving the demand for LMPG capacity. The increasing demand for cost-effective productivity has kept most of the laser mask writers ever manufactured running in production, sometimes long past their projected lifespan, and new writers continue to be built based on hardware developed some years ago.ii The data path is a case in point. While state-ofthe- art when first introduced, hardware-based data path systems are difficult to modify or add new features to meet the changing requirements of the market. As data volumes increase, design styles change, and new uses are found for laser writers, it is useful to consider a replacement for this critical subsystem. The availability of low-cost, high-performance, distributed computer systems combined with highly scalable EDA software lends itself well to creating an advanced data path system. EDA software, in routine production today, scales

  3. Segmenting the thoracic, abdominal and pelvic musculature on CT scans combining atlas-based model and active contour model

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Summers, Ronald M.

    2013-03-01

    Segmentation of the musculature is very important for accurate organ segmentation, analysis of body composition, and localization of tumors in the muscle. In research fields of computer assisted surgery and computer-aided diagnosis (CAD), muscle segmentation in CT images is a necessary pre-processing step. This task is particularly challenging due to the large variability in muscle structure and the overlap in intensity between muscle and internal organs. This problem has not been solved completely, especially for all of thoracic, abdominal and pelvic regions. We propose an automated system to segment the musculature on CT scans. The method combines an atlas-based model, an active contour model and prior segmentation of fat and bones. First, body contour, fat and bones are segmented using existing methods. Second, atlas-based models are pre-defined using anatomic knowledge at multiple key positions in the body to handle the large variability in muscle shape. Third, the atlas model is refined using active contour models (ACM) that are constrained using the pre-segmented bone and fat. Before refining using ACM, the initialized atlas model of next slice is updated using previous atlas. The muscle is segmented using threshold and smoothed in 3D volume space. Thoracic, abdominal and pelvic CT scans were used to evaluate our method, and five key position slices for each case were selected and manually labeled as the reference. Compared with the reference ground truth, the overlap ratio of true positives is 91.1%+/-3.5%, and that of false positives is 5.5%+/-4.2%.

  4. Dosimetric impact of tumor bed delineation variability based on 4DCT scan for external-beam partial breast irradiation.

    PubMed

    Guo, Bing; Li, Jianbin; Wang, Wei; Li, Fengxiang; Guo, Yanluan; Li, Yankang; Liu, Tonghai

    2015-01-01

    This study sought to evaluate the dosimetric impact of tumor bed delineation variability (based on clips, seroma or both clips and seroma) during external-beam partial breast irradiation (EB-PBI) planned utilizing four-dimensional computed tomography (4DCT) scans. 4DCT scans of 20 patients with a seroma clarity score (SCS) 3~5 and ≥5 surgical clips were included in this study. The combined volume of the tumor bed formed using clips, seroma, or both clips and seroma on the 10 phases of 4DCT was defined as the internal gross target volume (termed IGTVC, IGTVS and IGTVC+S, respectively). A 1.5-cm margin was added by defining the planning target volume (termed PTVC, PTVS and PTVC+S, respectively). Three treatment plans were established using the 4DCT images (termed EB-PBIC, EB-PBIS, EB-PBIC+S, respectively). The results showed that the volume of IGTVC+S was significantly larger than that of IGTVCand IGTVS. Similarly, the volume of PTVC+S was markedly larger than that of PTVC and PTVS. However, the PTV coverage for EB-PBIC+S was similar to that of EB-PBIC and EB-PBIS, and there were no significant differences in the homogeneity index or conformity index between the three treatment plans (P=0.878, 0.086). The EB-PBIS plan resulted in the lowest ipsilateral normal breast and ipsilateral lung doses compared with the EB-PBIC and EB-PBIC+S plans. To conclude, the volume variability delineated based on clips, seroma or both clips and seroma resulted in dosimetric variability for organs at risk, but did not show a marked influence on the dosimetric distribution.

  5. Thermal conductivity calibration for hot wire based dc scanning thermal microscopy

    NASA Astrophysics Data System (ADS)

    Lefèvre, Stéphane; Volz, Sebastian; Saulnier, Jean-Bernard; Fuentes, Catherine; Trannoy, Nathalie

    2003-04-01

    Thermal conductivity characterization with nanoscale spatial resolution can be performed by contact probe techniques only. The technique based on a hot anemometer wire probe mounted in an atomic force microscope is now a standard setup. However, no rigorous calibration procedure is provided so far in basic dc mode. While in contact with the sample surface, the electrical current I injected into the probe is controlled so that electrical resistance or the wire temperature is maintained by the Joule effect. The variation in current is assumed to be linearly related to the heat flux lost towards the sample and traditional calibration is carried out by relating the thermal conductivity of a set of samples to the measured current I. We provide analytical and numerical thermal modeling of the tip and sample to estimate the key heat transfer in a conductivity calibration procedure. A simple calibration expression is established that provides thermal conductivity as a function of the probe current or voltage measured. Finally, experimental data allow us to determine the unknown quantities of the parametric form obtained, i.e., the mean tip-sample contact radius and conductance.

  6. Template-based automatic extraction of the joint space of foot bones from CT scan

    NASA Astrophysics Data System (ADS)

    Park, Eunbi; Kim, Taeho; Park, Jinah

    2016-03-01

    Clean bone segmentation is critical in studying the joint anatomy for measuring the spacing between the bones. However, separation of the coupled bones in CT images is sometimes difficult due to ambiguous gray values coming from the noise and the heterogeneity of bone materials as well as narrowing of the joint space. For fine reconstruction of the individual local boundaries, manual operation is a common practice where the segmentation remains to be a bottleneck. In this paper, we present an automatic method for extracting the joint space by applying graph cut on Markov random field model to the region of interest (ROI) which is identified by a template of 3D bone structures. The template includes encoded articular surface which identifies the tight region of the high-intensity bone boundaries together with the fuzzy joint area of interest. The localized shape information from the template model within the ROI effectively separates the bones nearby. By narrowing the ROI down to the region including two types of tissue, the object extraction problem was reduced to binary segmentation and solved via graph cut. Based on the shape of a joint space marked by the template, the hard constraint was set by the initial seeds which were automatically generated from thresholding and morphological operations. The performance and the robustness of the proposed method are evaluated on 12 volumes of ankle CT data, where each volume includes a set of 4 tarsal bones (calcaneus, talus, navicular and cuboid).

  7. Data processing and quality evaluation of a boat-based mobile laser scanning system.

    PubMed

    Vaaja, Matti; Kukko, Antero; Kaartinen, Harri; Kurkela, Matti; Kasvi, Elina; Flener, Claude; Hyyppä, Hannu; Hyyppä, Juha; Järvelä, Juha; Alho, Petteri

    2013-09-17

    Mobile mapping systems (MMSs) are used for mapping topographic and urban features which are difficult and time consuming to measure with other instruments. The benefits of MMSs include efficient data collection and versatile usability. This paper investigates the data processing steps and quality of a boat-based mobile mapping system (BoMMS) data for generating terrain and vegetation points in a river environment. Our aim in data processing was to filter noise points, detect shorelines as well as points below water surface and conduct ground point classification. Previous studies of BoMMS have investigated elevation accuracies and usability in detection of fluvial erosion and deposition areas. The new findings concerning BoMMS data are that the improved data processing approach allows for identification of multipath reflections and shoreline delineation. We demonstrate the possibility to measure bathymetry data in shallow (0-1 m) and clear water. Furthermore, we evaluate for the first time the accuracy of the BoMMS ground points classification compared to manually classified data. We also demonstrate the spatial variations of the ground point density and assess elevation and vertical accuracies of the BoMMS data.

  8. Intensity-based hierarchical clustering in CT-scans: application to interactive segmentation in cardiology

    NASA Astrophysics Data System (ADS)

    Hadida, Jonathan; Desrosiers, Christian; Duong, Luc

    2011-03-01

    The segmentation of anatomical structures in Computed Tomography Angiography (CTA) is a pre-operative task useful in image guided surgery. Even though very robust and precise methods have been developed to help achieving a reliable segmentation (level sets, active contours, etc), it remains very time consuming both in terms of manual interactions and in terms of computation time. The goal of this study is to present a fast method to find coarse anatomical structures in CTA with few parameters, based on hierarchical clustering. The algorithm is organized as follows: first, a fast non-parametric histogram clustering method is proposed to compute a piecewise constant mask. A second step then indexes all the space-connected regions in the piecewise constant mask. Finally, a hierarchical clustering is achieved to build a graph representing the connections between the various regions in the piecewise constant mask. This step builds up a structural knowledge about the image. Several interactive features for segmentation are presented, for instance association or disassociation of anatomical structures. A comparison with the Mean-Shift algorithm is presented.

  9. Data Processing and Quality Evaluation of a Boat-Based Mobile Laser Scanning System

    PubMed Central

    Vaaja, Matti; Kukko, Antero; Kaartinen, Harri; Kurkela, Matti; Kasvi, Elina; Flener, Claude; Hyyppä, Hannu; Hyyppä, Juha; Järvelä, Juha; Alho, Petteri

    2013-01-01

    Mobile mapping systems (MMSs) are used for mapping topographic and urban features which are difficult and time consuming to measure with other instruments. The benefits of MMSs include efficient data collection and versatile usability. This paper investigates the data processing steps and quality of a boat-based mobile mapping system (BoMMS) data for generating terrain and vegetation points in a river environment. Our aim in data processing was to filter noise points, detect shorelines as well as points below water surface and conduct ground point classification. Previous studies of BoMMS have investigated elevation accuracies and usability in detection of fluvial erosion and deposition areas. The new findings concerning BoMMS data are that the improved data processing approach allows for identification of multipath reflections and shoreline delineation. We demonstrate the possibility to measure bathymetry data in shallow (0–1 m) and clear water. Furthermore, we evaluate for the first time the accuracy of the BoMMS ground points classification compared to manually classified data. We also demonstrate the spatial variations of the ground point density and assess elevation and vertical accuracies of the BoMMS data. PMID:24048340

  10. Tumor tracking based on correlation models in scanned ion beam therapy: an experimental study

    NASA Astrophysics Data System (ADS)

    Seregni, M.; Kaderka, R.; Fattori, G.; Riboldi, M.; Pella, A.; Constantinescu, A.; Saito, N.; Durante, M.; Cerveri, P.; Bert, C.; Baroni, G.

    2013-07-01

    Accurate dose delivery to extra-cranial lesions requires tumor motion compensation. An effective compensation can be achieved by real-time tracking of the target position, either measured in fluoroscopy or estimated through correlation models as a function of external surrogate motion. In this work, we integrated two internal/external correlation models (a state space model and an artificial neural network-based model) into a custom infra-red optical tracking system (OTS). Dedicated experiments were designed and conducted at GSI (Helmholtzzentrum für Schwerionenforschung). A robotic breathing phantom was used to reproduce regular and irregular internal target motion as well as external thorax motion. The position of a set of markers placed on the phantom thorax was measured with the OTS and used by the correlation models to infer the internal target position in real-time. Finally, the estimated target position was provided as input for the dynamic steering of a carbon ion beam. Geometric results showed that the correlation models transversal (2D) targeting error was always lower than 1.3 mm (root mean square). A significant decrease of the dosimetric error with respect to the uncompensated irradiation was achieved in four out of six experiments, demonstrating that phase shifts are the most critical irregularity for external/internal correlation models.

  11. Robust Initialization of Active Shape Models for Lung Segmentation in CT Scans: A Feature-Based Atlas Approach

    PubMed Central

    Beichel, Reinhard R.

    2014-01-01

    Model-based segmentation methods have the advantage of incorporating a priori shape information into the segmentation process but suffer from the drawback that the model must be initialized sufficiently close to the target. We propose a novel approach for initializing an active shape model (ASM) and apply it to 3D lung segmentation in CT scans. Our method constructs an atlas consisting of a set of representative lung features and an average lung shape. The ASM pose parameters are found by transforming the average lung shape based on an affine transform computed from matching features between the new image and representative lung features. Our evaluation on a diverse set of 190 images showed an average dice coefficient of 0.746 ± 0.068 for initialization and 0.974 ± 0.017 for subsequent segmentation, based on an independent reference standard. The mean absolute surface distance error was 0.948 ± 1.537 mm. The initialization as well as segmentation results showed a statistically significant improvement compared to four other approaches. The proposed initialization method can be generalized to other applications employing ASM-based segmentation. PMID:25400660

  12. Genetics Home Reference: limb-girdle muscular dystrophy

    MedlinePlus

    ... girdle muscular dystrophy is classified based on its inheritance pattern and genetic cause. Limb-girdle muscular dystrophy type ... includes forms of the disorder that have an inheritance pattern called autosomal dominant . Mutations in the LMNA gene ...

  13. Evaluation of Limb-Girdle Muscular Dystrophy

    ClinicalTrials.gov

    2014-03-06

    Becker Muscular Dystrophy; Limb-Girdle Muscular Dystrophy, Type 2A (Calpain-3 Deficiency); Limb-Girdle Muscular Dystrophy, Type 2B (Miyoshi Myopathy, Dysferlin Deficiency); Limb-Girdle Muscular Dystrophy, Type 2I (FKRP-deficiency)

  14. Structure design of lower limb exoskeletons for gait training

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Zhang, Ziqiang; Tao, Chunjing; Ji, Run

    2015-09-01

    Due to the close physical interaction between human and machine in process of gait training, lower limb exoskeletons should be safe, comfortable and able to smoothly transfer desired driving force/moments to the patients. Correlatively, in kinematics the exoskeletons are required to be compatible with human lower limbs and thereby to avoid the uncontrollable interactional loads at the human-machine interfaces. Such requirement makes the structure design of exoskeletons very difficult because the human-machine closed chains are complicated. In addition, both the axis misalignments and the kinematic character difference between the exoskeleton and human joints should be taken into account. By analyzing the DOF(degree of freedom) of the whole human-machine closed chain, the human-machine kinematic incompatibility of lower limb exoskeletons is studied. An effective method for the structure design of lower limb exoskeletons, which are kinematically compatible with human lower limb, is proposed. Applying this method, the structure synthesis of the lower limb exoskeletons containing only one-DOF revolute and prismatic joints is investigated; the feasible basic structures of exoskeletons are developed and classified into three different categories. With the consideration of quasi-anthropopathic feature, structural simplicity and wearable comfort of lower limb exoskeletons, a joint replacement and structure comparison based approach to select the ideal structures of lower limb exoskeletons is proposed, by which three optimal exoskeleton structures are obtained. This paper indicates that the human-machine closed chain formed by the exoskeleton and human lower limb should be an even-constrained kinematic system in order to avoid the uncontrollable human-machine interactional loads. The presented method for the structure design of lower limb exoskeletons is universal and simple, and hence can be applied to other kinds of wearable exoskeletons.

  15. Cross-sectional scanning tunneling microscopy of silicon-based heterostructures andp-n junctions

    NASA Astrophysics Data System (ADS)

    Tao, Meng

    This thesis describes the application of cross-sectional STM to the characterization of silicon-based device structures. Several difficulties have been overcome in the process of developing this new structural characterization method. A V-groove cleaving technique has been developed to help produce atomically-flat cleaved Si(111) surfaces, and cross-sectional STM has been performed on various samples prepared with this V-groove technique, including Si1-xGe x/Si heterostructures, ZnS/Si heterostructures, and Si p-n junctions. It is found on Si(111)2x1 that there is no preferential orientation for atomic steps, and the step structures are determined by the hexagonal symmetry of the atomic arrangement and the pi-bonded chains on Si(111)2x1. Two types of Si adatoms on Si(111)2x1 are identified. One sits on top of a single pi-bonded chain, and the other sits between two pi-bonded chains. Atomic-resolution images of cross sections of Si1-xGex/Si heterostructures reveal two strain relaxation mechanisms on the cleaved (111) surface. One is through stressing the substrate. The strained region in the substrate can extend several hundred Angstroms from the interface. The other is through defect formation, i.e. atomic steps, on the cleaved surface. This is equivalent to misfit dislocations in bulk strain relaxation. Cross-sectional STM of cleaved ZnS/Si heterostructures reveals that the ZnS layer sandwiched between Si substrate and Si cap layer has a high density of gap states. Possible reasons for the gap states include surface states on the cleaved ZnS(111) surface, and bulk defect states in the ZnS layer due to antiphase domains and intermixing of Si and ZnS during the high-temperature Si cap growth. The intermixing also makes the ZnS layer thicker than its targeted thickness. Atomic-resolution images of cross sections of p-n junctions and As dopant atoms indicate that As atoms on Si(111)2x1 are localized features about 7 A in diameter. Both As atoms in the top and second

  16. A reduced-order model-based study on the effect of intermittent pneumatic compression of limbs on the cardiovascular system.

    PubMed

    Maffiodo, Daniela; De Nisco, Giuseppe; Gallo, Diego; Audenino, Alberto; Morbiducci, Umberto; Ferraresi, Carlo

    2016-04-01

    This work investigates the effect that the application of intermittent pneumatic compression to lower limbs has on the cardiovascular system. Intermittent pneumatic compression can be applied to subjects with reduced or null mobility and can be useful for therapeutic purposes in sports recovery, deep vein thrombosis prevention and lymphedema drainage. However, intermittent pneumatic compression performance and the effectiveness are often difficult to predict. This study presents a reduced-order numerical model of the interaction between the cardiovascular system and the intermittent pneumatic compression device. The effect that different intermittent pneumatic compression operating conditions have on the overall circulation is investigated. Our findings confirm (1) that an overall positive effect on hemodynamics can be obtained by properly applying the intermittent pneumatic compression device and (2) that using intermittent pneumatic compression for cardiocirculatory recovery is feasible in subjects affected by lower limb disease.

  17. Management of Critical Limb Ischemia

    PubMed Central

    Kinlay, Scott

    2016-01-01

    Critical limb ischemia (CLI) is a clinical syndrome of ischemic pain at rest or tissue loss, such as non-healing ulcers or gangrene, related to peripheral artery disease. CLI has a high short-term risk of limb loss and cardiovascular events. Non-invasive or invasive angiography help determine the feasibility and approach to arterial revascularization. An “endovascular-first” approach is often advocated based on a lower procedural risk, however, specific patterns of disease may be best treated by open surgical revascularization. Balloon angioplasty and stenting form the backbone of endovascular techniques, with drug-eluting stents and drug-coated balloons offering low rates of repeat revascularization. Combined antegrade and retrograde approaches can increase success in long total occlusions. Below the knee, angiosome-directed angioplasty may lead to greater wound healing, but failing this, any straight line flow into the foot is pursued. Hybrid surgical techniques such as iliac stenting and common femoral endarterectomy are commonly used to reduce operative risk. Lower extremity bypass grafting is most successful with a good quality, long, single-segment autogenous vein of at least 3.5mm diameter. Minor amputations are often required for tissue loss as part of the treatment strategy. Major amputations (at or above the ankle) limit functional independence and their prevention is a key goal of CLI therapy. Medical therapy after revascularization targets risk factors for atherosclerosis and assesses wound healing and new or recurrent flow limiting disease. The ongoing NIH sponsored BEST-CLI study is a randomized trial of the contemporary endovascular versus open surgical techniques in patients with CLI. PMID:26858079

  18. Limb-Nadir Matching for Tropospheric NO2: A New Algorithm in the SCIAMACHY Operational Level 2 Processor

    NASA Astrophysics Data System (ADS)

    Meringer, Markus; Gretschany, Sergei; Lichtenberg, Gunter; Hilboll, Andreas; Richter, Andreas; Burrows, John P.

    2015-11-01

    SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric ChartographY) aboard ESA's environmental satellite ENVISAT observed the Earth's atmosphere in limb, nadir, and solar/lunar occultation geometries covering the UV–Visible to NIR spectral range. Limb and nadir geometries were the main operation modes for the retrieval of scientific data. The new version 6 of ESA's level 2 processor now provides for the first time an operational algorithm to combine measurements of these two geometries in order to generate new products. As a first instance the retrieval of tropospheric NO2 has been implemented based on IUP–Bremen's reference algorithm. We will detail the single processing steps performed by the operational limb–nadir matching algorithm and report the results of comparisons with the scientific tropospheric NO2 products of IUP and the Tropospheric Emission Monitoring Internet Service (TEMIS).

  19. Peripheral muscle dysfunction in COPD: lower limbs versus upper limbs.

    PubMed

    Miranda, Eduardo Foschini; Malaguti, Carla; Corso, Simone Dal

    2011-01-01

    In patients with COPD, the degree of functional impairment appears to differ between the upper and lower limbs. Significant dyspnea and fatigue have been reported by these patients when performing tasks with unsupported upper limbs and two mechanisms have been proposed to explain this fact: neuromechanical dysfunction of respiratory muscles; and changes in lung volume during such activities. The neuromechanical dysfunction seen in COPD patients during this type of exercise is related to changes in the breathing pattern, as well as to the simultaneity of afferent and efferent muscle stimuli, resulting in respiratory muscle asynchrony. In addition, the increased ventilation during upper limb exercise in patients with COPD leads to dynamic hyperinflation at different workloads. During lower limb exercises, the strength and endurance of the quadriceps muscle is lower in COPD patients than in healthy subjects. This could by explained by abnormal muscle metabolism (decreased aerobic capacity), dependence on glycolytic metabolism, and rapid accumulation of lactate during exercise. In comparison with lower limb exercises, upper limb exercises result in higher metabolic and ventilatory demands, as well as in a more intense sensation of dyspnea and greater fatigue. Because there are differences between the upper and lower limb muscles in terms of the morphological and functional adaptations in COPD patients, specific protocols for strength training and endurance should be developed and tested for the corresponding muscle groups.

  20. Acousto-optical deflection-based whole channel scanning for microchip isoelectric focusing with laser-induced fluorescence detection.

    PubMed

    Sanders, J C; Huang, Z; Landers, J P

    2001-12-01

    This paper describes the development of a technique amenable to the separation of proteins on a microchip by isoelectric focusing (IEF) with entire channel scanning laser-induced fluorescence detection using acousto-optical deflection (AOD). The ability to use AOD to scan the portions of or the entire length of an IEF separation channel allows for high-speed analysis since the mobilization step is circumvented with this technique. Employing no moving parts eliminates mechanical noise and, not only is there no loss of resolution, AOD scanning can potentially increase resolution. The ability of AOD to provide ultra-fast scanning rates (kHz timescale) allows for real-time imaging of the focusing process. This is demonstrated with the separation of naturally fluorescent proteins using entire channel (total scanning range of 2.4 cm) AOD-mediated scanning laser-induced fluorescence detection.

  1. The use of airborne laser scanning to develop a pixel-based stratification for a verified carbon offset project

    PubMed Central

    2011-01-01

    Background The voluntary carbon market is a new and growing market that is increasingly important to consider in managing forestland. Monitoring, reporting, and verifying carbon stocks and fluxes at a project level is the single largest direct cost of a forest carbon offset project. There are now many methods for estimating forest stocks with high accuracy that use both Airborne Laser Scanning (ALS) and high-resolution optical remote sensing data. However, many of these methods are not appropriate for use under existing carbon offset standards and most have not been field tested. Results This paper presents a pixel-based forest stratification method that uses both ALS and optical remote sensing data to optimally partition the variability across an ~10,000 ha forest ownership in Mendocino County, CA, USA. This new stratification approach improved the accuracy of the forest inventory, reduced the cost of field-based inventory, and provides a powerful tool for future management planning. This approach also details a method of determining the optimum pixel size to best partition a forest. Conclusions The use of ALS and optical remote sensing data can help reduce the cost of field inventory and can help to locate areas that need the most intensive inventory effort. This pixel-based stratification method may provide a cost-effective approach to reducing inventory costs over larger areas when the remote sensing data acquisition costs can be kept low on a per acre basis. PMID:22004847

  2. Image Quality Improvement in Adaptive Optics Scanning Laser Ophthalmoscopy Assisted Capillary Visualization Using B-spline-based Elastic Image Registration

    PubMed Central

    Uji, Akihito; Ooto, Sotaro; Hangai, Masanori; Arichika, Shigeta; Yoshimura, Nagahisa

    2013-01-01

    Purpose To investigate the effect of B-spline-based elastic image registration on adaptive optics scanning laser ophthalmoscopy (AO-SLO)-assisted capillary visualization. Methods AO-SLO videos were acquired from parafoveal areas in the eyes of healthy subjects and patients with various diseases. After nonlinear image registration, the image quality of capillary images constructed from AO-SLO videos using motion contrast enhancement was compared before and after B-spline-based elastic (nonlinear) image registration performed using ImageJ. For objective comparison of image quality, contrast-to-noise ratios (CNRS) for vessel images were calculated. For subjective comparison, experienced ophthalmologists ranked images on a 5-point scale. Results All AO-SLO videos were successfully stabilized by elastic image registration. CNR was significantly higher in capillary images stabilized by elastic image registration than in those stabilized without registration. The average ratio of CNR in images with elastic image registration to CNR in images without elastic image registration was 2.10 ± 1.73, with no significant difference in the ratio between patients and healthy subjects. Improvement of image quality was also supported by expert comparison. Conclusions Use of B-spline-based elastic image registration in AO-SLO-assisted capillary visualization was effective for enhancing image quality both objectively and subjectively. PMID:24265796

  3. A Novel Concept for Observing Land-Surface-Atmosphere Feedback Based on a Synergy of Scanning Lidar Systems

    NASA Astrophysics Data System (ADS)

    Wulfmeyer, V.; Turner, D. D.; Mauder, M.; Behrendt, A.; Ingwersen, J.; Streck, T.

    2015-12-01

    Improved simulations of land-surface-atmosphere interaction are fundamental for improving weather forecast and climate models. This requires observations of 2D fields of surface fluxes and the 3D structure of the atmospheric boundary layer simultaneously. A novel strategy is introduced for studying land-surface exchange and entrainment processes in the convective boundary layer (CBL) over complex terrain by means of a new generation of remote sensing systems. The sensor synergy consists of scanning Doppler lidar (DL), water-vapor differential absorption lidar (WVDIAL), and temperature rotational Raman lidar (TRRL) systems supported by surface in-situ measurements. The 2D measurements of surface fluxes are realized by the operation of a DL, a WVDIAL, and a TRRL along the same line-of-sight (LOS) in a range-height-indicator (RHI) mode whereas the other DL is performing a series of cross track RHI scans along this LOS. This new setup enables us to determine the friction velocity as well as surface sensible and latent heat fluxes by closing the complete set of Monin-Obukhov similarity relationships under a variety of surface layer stability conditions and different land cover and soil properties. As this closure is performed at all DL crossing points along the LOS, this is a strategy towards a 2D mapping of surface fluxes entirely based on remote sensing systems. Further details are presented at the conference. The second configuration is the simultaneous vertical profiling of vertical wind, humidity and temperature by DL, WVDIAL and TRRL so that latent heat and sensible heat flux profiles as well as a variety of different turbulent moments can be measured in the CBL. Consequently, by alternating of RHI scanning and vertical pointing modes, entrainment fluxes and surface fluxes can be measured almost simultaneously. This novel strategy has been realized for the first time during the Surface Atmospheric Boundary Layer Exchange (SABLE) campaign in the Kraichgau region

  4. Design and fabrication of an angle-scanning based platform for the construction of surface plasmon resonance biosensor

    NASA Astrophysics Data System (ADS)

    Hu, Jiandong; Cao, Baiqiong; Wang, Shun; Li, Jianwei; Wei, Wensong; Zhao, Yuanyuan; Hu, Xinran; Zhu, Juanhua; Jiang, Min; Sun, Xiaohui; Chen, Ruipeng; Ma, Liuzheng

    2016-03-01

    A sensing system for an angle-scanning optical surface-plasmon-resonance (SPR) based biosensor has been designed with a laser line generator in which a P polarizer is embedded to utilize as an excitation source for producing the surface plasmon wave. In this system, the emitting beam from the laser line generator is controlled to realize the angle-scanning using a variable speed direct current (DC) motor. The light beam reflected from the prism deposited with a 50 nm Au film is then captured using the area CCD array which was controlled by a personal computer (PC) via a universal serial bus (USB) interface. The photoelectric signals from the high speed digital camera (an area CCD array) were converted by a 16 bit A/D converter before it transferred to the PC. One of the advantages of this SPR biosensing platform is greatly demonstrated by the label-free and real-time bio-molecular analysis without moving the area CCD array by following the laser line generator. It also could provide a low-cost surface plasmon resonance platform to improve the detection range in the measurement of bioanalytes. The SPR curve displayed on the PC screen promptly is formed by the effective data from the image on the area CCD array and the sensing responses of the platform to bulk refractive indices were calibrated using various concentrations of ethanol solution. These ethanol concentrations indicated with volumetric fraction of 5%, 10%, 15%, 20%, and 25%, respectively, were experimented to validate the performance of the angle-scanning optic SPR biosensing platform. As a result, the SPR sensor was capable to detect a change in the refractive index of the ethanol solution with the relative high linearity at the correlation coefficient of 0.9842. This greatly enhanced detection range is obtained from the position relationship between the laser line generator and the right-angle prism to allow direct quantification of the samples over a wide range of concentrations.

  5. Addressing sub-scan variability of tundra snow properties in ground-based Ku- and X-band scatterometer observations

    NASA Astrophysics Data System (ADS)

    King, J. M.; Kasurak, A.; Kelly, R. E.; Duguay, C. R.; Derksen, C.; Rutter, N.; Sandells, M.; Watts, T.

    2012-12-01

    During the winter of 2010-2011 ground-based Ku- (17.2 GHz) and X-band (9.6 GHz) scatterometers were deployed near Churchill, Manitoba, Canada to evaluate the potential for dual-frequency observation of tundra snow properties. Field-based scatterometer observations when combined with in-situ snowpack properties and physically based models, provide the means necessary to develop and evaluate local scale property retrievals. To form meaningful analysis of the observed physical interaction space, potential sources of bias and error in the observed backscatter must be identified and quantified. This paper explores variation in observed Ku- and X-band backscatter in relation to the physical complexities of shallow tundra snow whose properties evolve at scales smaller than the observing instrument. The University of Waterloo scatterometer (UW-Scat) integrates observations over wide azimuth sweeps, several meters in length, to minimize errors resulting from radar fade and poor signal-to-noise ratios. Under ideal conditions, an assumption is made that the observed snow target is homogeneous. Despite an often-outward appearance of homogeneity, topographic elements of the Canadian open tundra produce significant local scale variability in snow properties, including snow water equivalent (SWE). Snow at open tundra sites observed during this campaign was found to vary by as much as 20 cm in depth and 40 mm in SWE within the scatterometer field of view. Previous studies suggest that changes in snow properties on this order will produce significant variation in backscatter, potentially introducing bias into products used for analysis. To assess the influence of sub-scan variability, extensive snow surveys were completed within the scatterometer field of view immediately after each scan at 32 sites. A standardized sampling protocol captured a grid of geo-located measurements, characterizing the horizontal variability of bulk properties including depth, density, and SWE. Based upon

  6. SU-E-T-127: Application of TG-119 for Evaluation of Proton Spot Scanning Based Planning and Treatment Delivery

    SciTech Connect

    Saini, J; Cao, N; Wong, T; Bowen, S; Bloch, C

    2015-06-15

    Purpose: The clinical test cases presented in AAPM TG-119 are used to evaluate the accuracy of treatment planning and delivery through spot scanning proton beams. Methods: An IBA spot scanning delivery system has been commissioned to be used with the RayStation treatment planning system. Various test cases provided in TG-119 were used for planning and delivery verification. The CT dataset and structures as provided by TG-119 were imported into a mock patient. The plans were optimized using the multi field optimization (MFO) to achieve the desired goals. The planner was given the flexibility to achieve the given dose-volume goals by creating appropriate objectives and constraints. Beams were delivered to a phantom and measurements were performed at multiple depths using the MatrixxPT detector array. The analyses were performed on beam by beam basis and quantified using the gamma index. A tolerance of 3%/3 mm in 2D was used for gamma index analysis along with dose threshold of 10%. Results: The clinical goals for targets and critical structures were met or improved for all cases except the C-Shape target with difficult constraints. The minimum gamma index using the 3%/3mm as a criterion is 93.3% for one of the planes measured for C-Shape target. Using 2%/2mm as a criterion, the minimum gamma index drops to 70%. Only Prostate target has all the planes above >90% pass using the 2%/2mm criterion. Conclusion: The overall accuracy of the treatment planning and delivery is deemed clinically acceptable. The test cases with highly modulated beams can have steep gradients in the dose profiles that can reduce the gamma index pass rate. Gamma analysis based on 3D data may be needed for routine use of 2%/2mm criterion. In addition, improvements in modelling of spot profiles in dose engine may be required for further improving the gamma index pass rate.

  7. Model-based x-ray energy spectrum estimation algorithm from CT scanning data with spectrum filter

    NASA Astrophysics Data System (ADS)

    Li, Lei; Wang, Lin-Yuan; Yan, Bin

    2016-10-01

    With the development of technology, the traditional X-ray CT can't meet the modern medical and industry needs for component distinguish and identification. This is due to the inconsistency of X-ray imaging system and reconstruction algorithm. In the current CT systems, X-ray spectrum produced by X-ray source is continuous in energy range determined by tube voltage and energy filter, and the attenuation coefficient of object is varied with the X-ray energy. So the distribution of X-ray energy spectrum plays an important role for beam-hardening correction, dual energy CT image reconstruction or dose calculation. However, due to high ill-condition and ill-posed feature of system equations of transmission measurement data, statistical fluctuations of X ray quantum and noise pollution, it is very hard to get stable and accurate spectrum estimation using existing methods. In this paper, a model-based X-ray energy spectrum estimation method from CT scanning data with energy spectrum filter is proposed. First, transmission measurement data were accurately acquired by CT scan and measurement using phantoms with different energy spectrum filter. Second, a physical meaningful X-ray tube spectrum model was established with weighted gaussian functions and priori information such as continuity of bremsstrahlung and specificity of characteristic emission and estimation information of average attenuation coefficient. The parameter in model was optimized to get the best estimation result for filtered spectrum. Finally, the original energy spectrum was reconstructed from filtered spectrum estimation with filter priori information. Experimental results demonstrate that the stability and accuracy of X ray energy spectrum estimation using the proposed method are improved significantly.

  8. Geophysical implications of Io limb profile data

    NASA Astrophysics Data System (ADS)

    Nimmo, F.; Thomas, P. C.

    2013-12-01

    Limb profiles can be used both to determine a body's long-wavelength shape, and to infer its averaged elastic thickness [1]. Here we apply previously-developed techniques [1] to analyze Galileo limb profiles for Io [2], for comparison with control-point network analysis [3]. We determine Io's long-wavelength topography at spherical harmonic degrees 3 and 4. The amplitude of the topography is +/- 0.5 km, small compared to the degree-2 (tidal and rotational) shape. The l=4 components contain 4 times more power than l=3, consistent with tidal heating playing a role in producing topography [e.g. 4]. However, the topographic pattern is anti-symmetric about the equator, which is not expected from tidal models. Nor does the topography correlate with the global pattern of volcanoes and mountains [5]. The variation in limb profile roughness with wavelength can be used to infer an elastic thickness [1,6]. In the case of Io, despite local mountains, overall the topography is quite smooth. The highest-resolution limb profiles suggest an elastic thickness of about 50 km, higher than that of other outer solar system satellites [1]. This value is consistent with previous estimates based on the existence of mountains [7] and expectations of a thick, cold lid resulting from Io's heat loss being dominated by erupting melt [8]. [1] Nimmo et al. JGR 2011 [2] Thomas et al. Icarus 1998 [3] Oberst and Schuster JGR 2004 [4] Ross et al. Icarus 1990 [5] Kirchoff et al. EPSL 2011 [6] Araki et al. Science 2009 [7] Carr et al. Icarus 1998 [8] O'Reilly and Davies GRL 1981 Io long-wavelength topography, obtained from limb profile data and expanded from l=m=3 to l=m=4. Contour interval 0.1 km.

  9. Recording Approach of Heritage Sites Based on Merging Point Clouds from High Resolution Photogrammetry and Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Grussenmeyer, P.; Alby, E.; Landes, T.; Koehl, M.; Guillemin, S.; Hullo, J. F.; Assali, P.; Smigiel, E.

    2012-07-01

    Different approaches and tools are required in Cultural Heritage Documentation to deal with the complexity of monuments and sites. The documentation process has strongly changed in the last few years, always driven by technology. Accurate documentation is closely relied to advances of technology (imaging sensors, high speed scanning, automation in recording and processing data) for the purposes of conservation works, management, appraisal, assessment of the structural condition, archiving, publication and research (Patias et al., 2008). We want to focus in this paper on the recording aspects of cultural heritage documentation, especially the generation of geometric and photorealistic 3D models for accurate reconstruction and visualization purposes. The selected approaches are based on the combination of photogrammetric dense matching and Terrestrial Laser Scanning (TLS) techniques. Both techniques have pros and cons and recent advances have changed the way of the recording approach. The choice of the best workflow relies on the site configuration, the performances of the sensors, and criteria as geometry, accuracy, resolution, georeferencing, texture, and of course processing time. TLS techniques (time of flight or phase shift systems) are widely used for recording large and complex objects and sites. Point cloud generation from images by dense stereo or multi-view matching can be used as an alternative or as a complementary method to TLS. Compared to TLS, the photogrammetric solution is a low cost one, as the acquisition system is limited to a high-performance digital camera and a few accessories only. Indeed, the stereo or multi-view matching process offers a cheap, flexible and accurate solution to get 3D point clouds. Moreover, the captured images might also be used for models texturing. Several software packages are available, whether web-based, open source or commercial. The main advantage of this photogrammetric or computer vision based technology is to

  10. Scanning electrochemical microscopy based evaluation of influence of pH on bioelectrochemical activity of yeast cells - Saccharomyces cerevisiae.

    PubMed

    Ramanavicius, A; Morkvenaite-Vilkonciene, I; Kisieliute, A; Petroniene, J; Ramanaviciene, A

    2017-01-01

    In this research scanning electrochemical microscopy was applied for the investigation of immobilized yeast Saccharomyces cerevisiae cells. Two redox mediators based system was applied in order to increase the efficiency of charge transfer from yeast cells. 9,10-phenanthrenequinone (PQ) was applied as a lipophilic redox mediator, which has the ability to cross the cell's membrane; another redox mediator was ferricyanide, which acted as a hydrophylic electron acceptor able to transfer electrons from the PQ to the working electrode of SECM. Hill's function was applied to determine the optimal pH for this described SECM-based system. The influence of pH on cell viability could be well described by Hill's function. It was determined that at pH 6.5 the PQ has a minimal toxic influence on yeast cells, and the kinetics of metabolic processes in cells as well as electron transfer rate achieved in consecutive action of both redox mediators were appropriate to achieve optimal current signals.

  11. Study of Upper Albian rudist buildups in the Edwards Formation using ground-based hyperspectral imaging and terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Krupnik, Diana; Khan, Shuhab; Okyay, Unal; Hartzell, Preston; Zhou, Hua-Wei

    2016-11-01

    Ground-based hyperspectral imaging is used for development of digital outcrop models which can facilitate detailed qualitative and quantitative sedimentological analysis and augment the study of depositional environment, diagenetic processes, and hydrocarbon reservoir characterization in areas which are physically inaccessible. For this investigation, ground-based hyperspectral imaging is combined with terrestrial laser scanning to produce mineralogical maps of Late Albian rudist buildups of the Edwards formation in the Lake Georgetown Spillway in Williamson County, Texas. The Edwards Formation consists of shallow water deposits of reef and associated interreef facies. It is an aquifer in western Texas and was investigated as a hydrocarbon play in south Texas. Hyperspectral data were registered to a geometrically accurate laser point cloud-generated mesh with sub-pixel accuracy and were used to map compositional variation by distinguishing spectral properties unique to each material. More calcitic flat-topped toucasid-rich bioherm facies were distinguished from overlying porous sucrosic dolostones, and peloid wackestones and packstones of back-reef facies. Ground truth was established by petrographic study of samples from this area. This research integrates high-resolution datasets to analyze geometrical and compositional properties of this carbonate formation at a finer scale than traditional methods have achieved and to model the geometry and composition of rudist buildups.

  12. Fluid mechanics of blood flow in human fetal left ventricles based on patient-specific 4D ultrasound scans.

    PubMed

    Lai, Chang Quan; Lim, Guat Ling; Jamil, Muhammad; Mattar, Citra Nurfarah Zaini; Biswas, Arijit; Yap, Choon Hwai

    2016-10-01

    The mechanics of intracardiac blood flow and the epigenetic influence it exerts over the heart function have been the subjects of intense research lately. Fetal intracardiac flows are especially useful for gaining insights into the development of congenital heart diseases, but have not received due attention thus far, most likely because of technical difficulties in collecting sufficient intracardiac flow data in a safe manner. Here, we circumvent such obstacles by employing 4D STIC ultrasound scans to quantify the fetal heart motion in three normal 20-week fetuses, subsequently performing 3D computational fluid dynamics simulations on the left ventricles based on these patient-specific heart movements. Analysis of the simulation results shows that there are significant differences between fetal and adult ventricular blood flows which arise because of dissimilar heart morphology, E/A ratio, diastolic-systolic duration ratio, and heart rate. The formations of ventricular vortex rings were observed for both E- and A-wave in the flow simulations. These vortices had sufficient momentum to last until the end of diastole and were responsible for generating significant wall shear stresses on the myocardial endothelium, as well as helicity in systolic outflow. Based on findings from previous studies, we hypothesized that these vortex-induced flow properties play an important role in sustaining the efficiency of diastolic filling, systolic pumping, and cardiovascular flow in normal fetal hearts.

  13. Wavelength-Scanning SPR Imaging Sensors Based on an Acousto-Optic Tunable Filter and a White Light Laser.

    PubMed

    Zeng, Youjun; Wang, Lei; Wu, Shu-Yuen; He, Jianan; Qu, Junle; Li, Xuejin; Ho, Ho-Pui; Gu, Dayong; Gao, Bruce Zhi; Shao, Yonghong

    2017-01-05

    A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and high sensitivity offered by the spectral approach with multiplexed high-throughput data collection and a two-dimensional (2D) biosensor array. The key feature is the use of AOTF to realize wavelength scan from a white laser source and thus to achieve fast tracking of the SPR dip movement caused by target molecules binding to the sensor surface. Experimental results show that the system is capable of completing a SPR dip measurement within 0.35 s. To the best of our knowledge, this is the fastest time ever reported in the literature for imaging spectral interrogation. Based on a spectral window with a width of approximately 100 nm, a dynamic detection range and resolution of 4.63 × 10(-2) refractive index unit (RIU) and 1.27 × 10(-6) RIU achieved in a 2D-array sensor is reported here. The spectral SPR imaging sensor scheme has the capability of performing fast high-throughput detection of biomolecular interactions from 2D sensor arrays. The design has no mechanical moving parts, thus making the scheme completely solid-state.

  14. Wavelength-Scanning SPR Imaging Sensors Based on an Acousto-Optic Tunable Filter and a White Light Laser

    PubMed Central

    Zeng, Youjun; Wang, Lei; Wu, Shu-Yuen; He, Jianan; Qu, Junle; Li, Xuejin; Ho, Ho-Pui; Gu, Dayong; Gao, Bruce Zhi; Shao, Yonghong

    2017-01-01

    A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and high sensitivity offered by the spectral approach with multiplexed high-throughput data collection and a two-dimensional (2D) biosensor array. The key feature is the use of AOTF to realize wavelength scan from a white laser source and thus to achieve fast tracking of the SPR dip movement caused by target molecules binding to the sensor surface. Experimental results show that the system is capable of completing a SPR dip measurement within 0.35 s. To the best of our knowledge, this is the fastest time ever reported in the literature for imaging spectral interrogation. Based on a spectral window with a width of approximately 100 nm, a dynamic detection range and resolution of 4.63 × 10−2 refractive index unit (RIU) and 1.27 × 10−6 RIU achieved in a 2D-array sensor is reported here. The spectral SPR imaging sensor scheme has the capability of performing fast high-throughput detection of biomolecular interactions from 2D sensor arrays. The design has no mechanical moving parts, thus making the scheme completely solid-state. PMID:28067766

  15. A novel sedimentological method based on CT-scanning: Use for tomographic characterization of the Galicia Interior Basin

    NASA Astrophysics Data System (ADS)

    Mena, Anxo; Francés, Guillermo; Pérez-Arlucea, Marta; Aguiar, Pablo; Barreiro-Vázquez, José Daniel; Iglesias, Alfredo; Barreiro-Lois, Andrés

    2015-05-01

    Non-destructive techniques of core analysis, especially of marine cores, are being broadly employed for sedimentary, paleoceanographic and paleoclimate research. In particular, Computed Tomography scanning (CT-scanning) allows acquisition of 3D and 2D images, according to desired planes, and thus the identification of sedimentary structures, large grains and their distributions as well as direct measurements of material densities. The most significant contribution of this technique is the possibility of getting results before opening the core. In this work CT-scan data obtained for five cores from the Galicia Interior Basin (GIB, NW Peninsula Iberia) are presented and discussed, focussing on (1) methodology of the CT-scan use, (2) tomographic descr